Deck Building
Now you are staring at a pile of cards and have to make a deck out of it. Of the forty-two cards you drafted, you'll only be using about twenty-three of them in your deck (the rest will be lands).
I'll lay out the basics as a set of rules here. As with all rules, there are times to break them, but for a beginning drafter, I would stick to these until I was more experienced.
Rule 1. Play a forty-card deck. This may sound obvious, but it can be tempting to play that extra card when facing a tough decision about which card to cut. Don't fall for this trap. Play your forty best cards, and not a single one more.
Rule 2. Play seventeen lands. Do not skimp on this! seventeen lands is the minimum; don't play sixteen even if you think it's okay. You need seventeen lands for your deck to function in a normal Limited setting. Yes, there will be exceptions down the line, but seventeen lands is a great starting point.
Rule 3. Play at least fifteen creatures. This one is a bit more flexible, but if you find yourself with a draft deck containing ten or eleven creatures, you probably went wrong somewhere in your draft. If you have eighteen creatures, that's ok. Creatures are the most important thing in Limited, and having too many is far better than having too few. Again, this is more flexible than the lands; if you end up with fourteen creatures, it's fine.
Rule 4. Play a two-color deck. This is also a more flexible one down the line, but when you are starting out, your decks will perform better if you exercise discipline and stick to just two colors. You will experience better draws, fewer mulligans, and more consistent performance from your deck.
That's it. If you follow these rules, and think about them while you are drafting, you'll draft reasonable decks most of the time,\ and give yourself a shot at winning even if you are new to drafting.
Down the Line
While these rules are a solid starting point for a new drafter, one of the beautiful things about Booster Draft is how diverse it can become once you are settled in. I have won drafts with decks containing five creatures. I have also won drafts (and lost quite a few) with decks playing all five colors. There is no limit to how you can express your creativity and deck-building skill. Still, you are best served with a good foundation under you before starting to get too fancy.
Booster Draft is a challenging format. It takes a long time to master, but I have found that while it can seem intimidating at first, it's not nearly as daunting as many people assume. Most players will settle into two colors fairly quickly in a draft. This means that when they look at a full pack, they are really only looking at the cards in their colors, which is much easier than trying to take in the whole pack at once.
