To draft a non-traditional deck you will need to pick up a number of cards that are of little value to the other players at your table. Those cards might be things such as Zephyr Sprites, Jackal Familiars (arf, arf) and Trumpet Blasts for your hyper-aggressive blue-red deck. They might be Dampen Thoughts and a host of other arcane spells that mean little to other players, such as Ethereal Haze and Peer Through Depths. It could be Centaur Safeguards or anything that can gain you life in your Searing Meditation deck.
That's not to say that you won't also be interested in picking up cards that other people would also find valuable, such as good removal, card drawing, bombs, etc. But the majority of your mid pack picks will be dramatically different from what would be appropriate for a "normal" deck.
While decks such as hyper-aggressive blue-red in Magic 2010 tend to be attractive because in large part they are easy to put together, they are generally considered non-traditional simply because they revolve around so many "bad" cards. This means that if you start taking things like Jackal Familiars early and the aggressive cards dry up, you will often be down some picks. But if you are drafting blue-red and you notice a lot of late aggressive cards making their way to you, there's no reason why you won't be able to move into the archetype even if you are midway through pack two.
However, decks that are truly wacky do not tend to have that ability to overlap with traditional strategies. A thoroughly non-traditional deck will usually need a lot of cards that offer basically zero value to the other players at the table. But even though the other players at the table aren't placing a value on them, you still need them to be there.
Mill decks are usually pretty tough to put together in Limited, but when things fall into place everyone better watch out because a lot cards are about to hit the graveyard.
Drafting a Non-traditional Deck
When do you start drafting a non-traditional deck?
If you are reasonably confident that you won't have any competition for your off-the-wall strategy, and you don't need an extremely hard-to-find set of cards for your deck to come together, then you will often be able to start forcing your deck with the very first pick of the draft. Now this doesn't mean you have to do something ridiculous.
Even if you think that the Zephyr Sprite in your (admittedly weak) opening pack would be the best card for the deck that you want to end up with, you might decide that it's worth it to take a card that is better in the abstract, especially as the Zephyr Sprite stands a good chance of making its way back to you with your ninth pick. But you also might decide that you should just go for that one mana 1/1 flier, or that Ethereal Haze for your Dampen Thought deck, or that Frogmite for your affinity deck.
Whether you start your draft in fourth gear, or you gradually creep your way there, if your deck does not require you to obtain a particularly obscure set of cards, you will probably be fine.
But if you need a specific, hard-to-come-by set of cards, you will have to wait to see if those cards are even in the draft before you can go for it.
For example, dedicated M10 mill decks depend heavily on one card and one card only. Sure, Burning Inquiry can help with you deplete your opponent's library as can a couple of rares such as Traumatize, Jace Beleren and Twincast. In order to put together a focused mill deck in an M10 draft you are going to need to pick up a bunch of Tome Scours. And that's not easy to do in a draft with eight (or fewer) players even if you are the only person at your table trying to deck your opponents.
I think that a good M10 mill deck needs at least 7 or 8 Tome Scours. If you get any more than that, your deck is probably going to be awesome. Any less and you're going to have a bit of an uphill climb.
Once you have begun drafting the Tome Scour deck, and you have about two or three copies of the crucial blue common, you can be fairly confident that no one else at the table is going to try to deck their opponents. That means that you will probably be able to get your Tome Scours to table.
Even if you have an eye for the Tome Scour draft, you won't be able to pull it off more than once every couple of drafts. Thus, the correct way to attempt to draft it is to pick normally during the first pack, grabbing any Tome Scours that you see late, but not giving up anything significant to get them. During the second pack, if you already have 4-plus Tome Scours, you can grab more Tome Scours over even very solid cards. But if you only have 2-3 Tome Scours, you should continue to draft somewhat normally, however with an eye towards a more defensive set of cards in case the mill plan actually comes together.
Once you get to pack three, however, you will be able to let your set of cards dictate your picks pretty clearly. If you already have 8 Tome Scours, it becomes reasonable to take additional Tome Scours over even top-notch cards. If you don't have many Tome Scours going into the third pack, you are going to have to completely abandon the idea (unless there are somehow a ton of Tome Scours in the third set of packs) and figure out the best deck that you can draft given what you already have to work with.
If you're trying to draft a mill deck in Zendikar, you will need to get at least two Hedron Crabs. You might also be able to pick up an Archive Trap to help speed up your deck, but without those Hedron Crabs you won't be decking anyone.
So if you open up your first pack and you see a Hedron Crab and not much else, you might go for the deadliest catch, hoping to find more crabs before the end of your draft. But you still need those Hedron Crabs to deck your opponents. This means that you can't force a milling deck unless you already have a Hedron Crab or two in your deck.
While you can't plan on seeing Hedron Crabs, you can actively draft the deck that they are best in, blue-green landfall. You can position your deck in such a way that Hedron Crabs would be awesome for you, but you will have to make sure that your deck will function just as well if you are killing your opponent with Baloth Woodcrashers, Territorial Baloths, and Windrider Eels.
Mill 'em and Kill 'em
If you are drafting mill cards with the intention of playing them, you will eventually have to ask yourself just how dedicated is your mill deck?
Sometimes you won't get enough pieces to make a truly dedicated mill deck, but you will have enough for a mill sub-theme. This can be used as a sort of alternate win condition in your otherwise normal, controlling deck. You might normally look to kill your opponent with fliers or big ground creatures in your blue-green landfall deck, but if you have a Hedron Crab you might use that to rip through your opponent's deck while the rest of your creatures stay on defense.
However, your mill package probably won't do much for you in your aggressive deck (though you might want to board it in if your opponent's deck is particularly slow and controlling), as there's pretty much nothing worse than drawing a card that cannot damage your opponent when you just desperately need to punch in those last few points of damage before your opponent takes over the game with his or her larger, more powerful spells.
The ideal creatures for a mill deck are good on defense, but unless you have enough cards for a truly dedicated mill strategy (such as in an M10 Tome Scour deck) you will need to have some creatures with meaningful offensive capabilities in case you have to go for plan B(eatdown).
For example, Living Tsunami is an ideal card for a Hedron Crab-fueled mill deck. It provides you with a legitimate alternate win condition, it's quite good on defense and it powers up your landfall. Merfolk Seastalkers, Sky Ruin Drakes, and Windrider Eels are all cards that you would be happy to have in your mill deck because of their abilities to impact the game in a way that is meaningful for you on offense and on defense.
However, Steppe Lynx is exactly the kind of card that you would not want to have it in your mill deck. It does damage in small increments, it doesn't block, and its value gradually approaches zero (for a mill deck at least) as the game progresses. Steppe Lynx really only has a meaningful effect if you are looking to overwhelm your opponents, or win by dealing incremental amounts of damage. Because your controlling mill deck shouldn't interested in either of these things, you're going to want to leave those 0/1s in the sideboard.
An Aggressive Defense
It's particularly important for your dedicated mill deck not to fall behind early in the game. If your opponent is smashing you with Steppe Lynxes and Plated Geopedes, and you don't have any answers, you just aren't going to have the time to Hedron Crab your opponent out. It's fine if your opponent's big spells are good enough to beat you, as you will be able to topple your opponent's library by the time the late game rolls around. But you need to make sure you get to the late game.
It's important to understand, for both traditional and non-traditional strategies, that just because you are playing a "slow" deck, that doesn't mean that it's okay for your spells to be expensive. In fact, if your deck is slow, it becomes particularly important for you to have a large quantity of cheap spells that will allow you to drag out the game to the point where your more powerful cards can take things home for you.
This is why cards such as Kraken Hatchling are particularly important in mill decks. They buy you valuable time, allowing everything else to come online.
Because your mill deck revolves primarily around cheap and expensive spells, you will need to find good things to do when you have three and four mana. That means that you will be able to put those Cancels and Summoner's Banes to work in a way that most other decks simply cannot. It's generally quite painful for a deck to pass turn four without a play in order to leave up Summoner's Bane mana. But if you don't have any good plays for turn four, having a Summoner's Bane can be incredible.
These counterspells can do wonders for you both early and midway through the game actively filling out your curve, and late in the game to insure that your opponent can't turn the tide at the last moment.
Be aware that many cards can deviate dramatically from their normal value when you have a non-traditional deck. Remember, once you are already going off the straight and narrow, don't be afraid to completely rethink a lot of what you "know" about drafting.