In this case I want to talk about early decisions that are more pedestrian. For example, suppose in the first round of a Ravnica booster draft you have the following opening hand going first:
Play a land, of course. But do you play a Plains or a Forest? I didn't give you enough information to make that decision. The question you need to answer is: Are there any cards in this deck that can be cast for or but not , or potentially or but not or ? If your deck contains a Boros Guildmage you need to play the Plains first in case you draw Boros Guildmage on your second turn. If you have a Golgari Guildmage, you need to play a Forest for the same reason.
Those are the easy scenarios. For those who think they're not worth mentioning, I watched a world class player play the wrong land earlier this week. Now suppose your deck has one copy of both Guildmages in it but no other spells that you might prove unable to cast if you choose the wrong land.
At this point you have to ask which Guildmage is more important on the second turn. The Golgari Guildmage has two expensive long term abilities. That's powerful later in the game but early in the game those abilities are too expensive to use. Boros Guildmage has two inexpensive abilities that can impact the game as early as turn three and either allow you to attack or block where you couldn't do the same with Golgari Guildmage. Therefore you play the Plains on turn one to maximize the value of your second turn.
You want to make this decision for your deck when you build it. In constructed decks with two or more colors of mana this decision can even impact what cards you put into your deck. If you are already playing Boros Guildmage, playing a card that costs that you might also want to play on turn two becomes a liability. Even during the draft this is something that might be worth considering if a decision is close. It also is a strong sign that your mana may be strained in other ways as well.
Now for the final possibility: You have no cards that can be cast for or that cannot be cast for . No matter what happens, you will have no trouble casting your colored spells on schedule.
Most people will play a land at random in this spot or lead with the land that is part of their most important color. I want to dig deeper because I think that this is a mistake. It's a small mistake to be sure but that doesn't mean that it shouldn't be fixed. This decision is about information. Your opponent will see a Plains or Forest and then start making his decisions based on that information. If it is safe, then on your second turn you can play a second copy of the land you played first and your opponent will have to play an additional turn without knowing about your other color or colors.
Your actions may continue to mislead your opponent even after you reveal all of your lands because most people will play lands more central to the deck first given the choice. First impressions also count for a lot. Get him thinking that the deck is white and then add in some green and you paint a slightly different picture than if you get him thinking it is green and then add in white. There's also the potential to make him think you got lucky and drew the lands you need if you want to play that type of game.
A final consideration is the possibility of land destruction. Which land will your opponent go after if he has the ability to go after your lands? If there's a good chance he will destroy a land this trumps most other considerations easily. In Ravnica limited there is not much fear of land destruction but it does exist. In this example you can survive the loss of any one land without trouble. In situations where you cannot afford to lose a land but need more than one on the board (which means you can't hide it until you need it) you generally want to lead with it for reasons I went over in Mind Over Urzatron. In this case I don't think this needs to be a concern.
So given your goal is to mislead, which land is more valuable to achieving that end? In this case you should play a Plains, then another Plains on turn two and only then double back for Forests. If your opponent thinks you may be playing the Boros guild he will make the wrong decisions given your hand. If he thinks you are Golgari then he will probably make better decisions because your hand is going to play a lot more like a Golgari deck than a Boros deck – it is a slow ground attack. The contents of your deck could still swing this either way with other information, but with those contents undefined I would play the Plains.
Mike Turian has said that he has never played a perfect game of Magic. I think he is wrong about that, but when he said that this is the type of thing he was referring to, along with even smaller things like facial expressions that could be considered tells. The timing involved in the playing of these lands can even be important if your opponent is paying attention. Thinking indicates that you have a decision to make, and knowing when an opponent has to think can reveal vital information about their hand. I believe that I got a lot of edges in my professional career because I trained myself to make as many decisions as possible without needing to think about them: I would think before the match or on the opponents' turn, so my opponent never had any idea what was going on.
There are two other common first turn decisions that involve the development of your mana base: Ravnica land versus Painland and Birds of Paradise versus Llanowar Elves. In both cases the key is an analysis of risk versus reward.
Painland versus Ravnica Land
In this case you clearly start the game with Temple Garden. On turn two you'll be casting Watchwolf so by the end of your second turn you will be at eighteen life whether you start with Brushland or Temple Garden. On your third turn you will be better off having the Temple Garden already in play, so that's how you start the game.
The real question comes in situations where you don't see when you'll have to give that second point of damage back. For example, suppose this hand had Vinelasher Kudzu instead of Watchwolf.
There are two scenarios. In scenario one you lead with the Temple Garden and are essentially pain-free for the rest of the game unless you have a spell or need to play another Temple Garden untapped to avoid being one mana short. If either of these things happen, you would have taken the same pain in scenario two as well. By investing two life points now you are solving your color problems in the future. Leading with the Brushland only costs one life point but you won't be out of the woods until you either find a way to put the Temple Garden into play tapped without it costing you time. The problem is now on your third turn: You'll probably want to Scatter the Seeds, but that will require three lands to go with your two creatures. That means that if you don't draw a non-Temple Garden land in the next two turns you'll have to pay the two life anyway and be a life point behind. It looks like there's a very good chance that there will be no good time to play the Temple Garden.
For that reason, I would still pull the band-aid off right away and play the Temple Garden on turn one.
I have been playing with the Ravnica lands for a long time now, longer than they've been public knowledge, and my experience has been clear. If there is any question about which land to lead with you probably want to pay the two life as soon as possible. The reason for this is that almost all of the hidden advantages are on the side of the Temple Garden. When you play the Temple Garden you've bought an insurance policy. On every turn you will have better and cheaper mana than if you led with Brushland. The cost of this insurance is one life point. The worst situations are those in which you end up paying multiple points of pain to Brushland to cast the cards you draw, still trying to avoid paying the two life for Temple Garden once you start paying for Brushland. In order to play Brushland on the first turn you need a hand where you know which turn you'll be playing the Temple Garden – for example, if you had a one mana artifact you wanted to play on turn two. Alternately, you might have Selesnya Sanctuary in your hand and know that the land you play is returning to your hand. The key lesson here is that you have to remember all the individually unlikely things that could be played by your opponent or could come off the top of your library. Each one is unlikely on its own but together they add up.
That leads into the last decision, Birds of Paradise against Llanowar Elves. The natural instinct is to lead with Llanowar Elves whenever you can in order to get in an extra point or two of damage and often those who lead with a Bird soon wonder why they gave up that extra point of damage. The problem often is that you're risking a large setback to gain a small advantage. Odds are you will profit but it often ends up still being a bad risk. For example, suppose Levy's deck from Pro Tour: Los Angeles (you'll have to scroll down) opens with this hand:
You're going first and have no idea what your opponent is playing so you have decided not to cast Cabal Therapy on turn one.
As you probably guessed from the prologue I believe you should lead with Birds of Paradise. In this case, your reason is Hypnotic Specter. If you draw Hypnotic Specter then you will be very thankful that you played Birds of Paradise, and if you draw Dark Confidant then you can cast Dark Confidant and Cabal Therapy on turn two. That overrides the fact that you are far more likely to be giving up a free point of damage. The ability to play Hypnotic Specter or cast both Dark Confidant and Cabal Therapy is far, far more important than the ability to attack for one.
This strategic reasoning here is similar to the reason we're all willing to play Ravnica lands and painlands: The stability of your mana base in the first few turns is far more important than a few points of damage. An early play can result in a gain or loss of tempo that swings the entire game. That doesn't mean that Birds of Paradise is a better or worse card than Llanowar Elves. It does mean that Birds of Paradise is often a better card on the first turn even if you don't see the immediate need to draw a color of mana from it other than green. There are situations where you know you don't need the color and can play the Elves first, especially when you play a dual land first or are playing a deck where the Birds are there to be Elves five through eight, but the strength of Llanowar Elves comes later in the game. On turn twenty you would rather draw Llanowar Elves. On turn one you probably want Birds of Paradise.
Early on both players have a lot of life points but no mana, permanents or information. Resources that are scarce have to be treated like gold, which is why cards that help with these resources early on are so valuable even if they do little or nothing later in the game. Other resources can be spent aggressively. As both the players and the decks become stronger more and more of your fate will be decided by what happens in the first few turns. Anything that gives you even a small edge in those decisions is worth investing time to pursue.