for me it is all about either staying alive long enough to beat them, or beat them as quickly as possable and hope you don't die in the proscess (I usually pic the first one). If you want to survive you usually want to put white in your deck ( although I do have a black/blue deck that works, and red land destruction helps you survive). Well from there you pic out about 10 to 20 cards that help you live (orim's prayer, blessed reversal, orim, samite healer...), I usually have closer to ten of those type of cards. Anyway, after that is done you pic some favorites to kill off you opponent, this includes combos, spells, creatures, basicly anything outside of your goal. Finally, after you have 30 to 40 of those cards you put in land. If you have lots of colors put in duel landds or something like them, if you only have one or two put in fast mana. Things like that.