Magic: The Gathering/Booster Draft
Booster Drafting is a method of constructing decks in Magic: The Gathering
This format is sanctioned by DCI and occurs at almost every prerelease. Many stores also make the last Friday Night Magic Tournament of the month a booster draft.
The Process 
Each player is given three booster packs.
Each player opens one pack and removes one card for themselves.
They then take the remaining cards and pass them to the player on their left.
They subsequently receive cards from the player on their right.
They remove a card from the new set of cards and pass it to their left.
This process continues until there are no more cards.
Players then open their second booster pack.
They repeat the process, this time passing cards to their right.
When there are no more cards, they open their final booster pack.
They repeat the process, this time passing cards to their left again.
After exhausting all three booster packs, each player should have selected and obtained 45 cards.
They combine as many or as few cards from the ones they just selected with any amount of basic lands they desire. This becomes their deck. This deck must have a minimum of 40 cards.
Players then compete tournament style to win a prize of some sort (normally additional packs).
At informal/casual drafts, a rule can be set in place that forces players to return all of the rares they drafted into one center pile after the tournament is over. The player who came in first selects a rare to keep, then the player who came in second, and so on. After the last player picks a rare, it starts over again with the player who came in first. Playing a match like this does two things, it gives the winner a prize without having the players to spend money on additional packs, and it prevents rare drafting to make the matches more competitive and fun.
Sometimes the rule is adjusted to make players return all rares and uncommons. This makes the tournament more competitive, but the cards-to-keep selection process afterwards is much longer.
Deck Building Strategy
Because the decks are only 40 cards and most of the cards in a booster pack are small creatures or spells with small mana costs, it is a generally good idea to build a fast deck. Also, because you will rarely get more than one or two of a good card, it is not a good idea to build the deck around it, featuring complex combos and whatnot. If a combo requires 3 cards, and you only have one of each, you cannot rely on drawing it every game.
Card Picking Strategy
Often it is difficult to decide what tribe and/or colors to run. At first you only see 7 of the 84 cards you can choose from. It is normal to begin thinking you want to play one color and then switch to another color part way into drafting. This normally happens when you see a particular good card in another color or notice that many players are not drafting cards from a particular color. If you notice that most of the cards passed to you are blue and there are never any good white cards, chances are a large number of people are running mono white, white/green, etc. This a good sign you should switch from white to blue. The less people who want blue cards, the better chance you have of getting good blue cards.
In this act, players select a rare card from the set of cards handed to them, not because it will benefit their deck, but because the card is worth a large amount or because the card would go well in another deck of theirs at a later date.
In this act, players select a powerful card from the set of cards handed to them, not because it will benefit their deck, but because the card is exceptionally powerful and they don't want anyone to use it against them. Even if the card is worthless to them, making sure no one else has it could mean the difference between winning or losing the tournament.