One strategy I've found helpful when building a deck is to think about major themes/categories of characters while I'm sifting through my cards (i.e. Priests, Demons, Pharisees, Angels, etc.). Next, I figure out what kinds of characters I have, then I start to find common enhancements and synergies between characters (i.e banding, protect certain characters, etc). After I have a few piles of themes, then I start to weed out the excess cards that do not add much value. The last part I usually look at are the misc cards (Dominants, Sites, Artifacts, LS, etc.) and then add those based one the characters I'm playing and my play style. And viola! You have a deck! I would recommend play testing your deck against a starter deck or something else you may have whipped up while assembling your tournament deck (I'll be doing that this evening, in preparation for Saturday).
But I agree with Reth, take a look at some decks on the message boards or even get some pointers from some theme decks from the sites Reth mentioned. They can really help give you an idea of some cards to play, and cards you'd like to get in order to play a certain theme, and the prices are decent for outright buying a theme or evening buying some battle decks to test your ensemble.
Overall, play a deck you can have fun with. Don't let the stress of building a great deck spoil the joy of playing the game. I've made that mistake.
