Besides the forums here, you could also take The Ideal Guild Quiz
. From the front page they state:
If you are seeking a guild in the Star Wars: The Old Republic community, you are faced with the daunting task of narrowing an enormous selection of guilds.
Each guild embodies a unique set of traits, each of which you - the discerning guild seeker - must review to be absolutely certain of your compatibility (after all, selecting a guild is a decision that could stay with you for years to come).
The proper choice may unlock countless friendships, whereas a rushed decision might just as easily lead you down a path of discontent (a mistake that many gamers are intimately familiar with).
To mitigate these concerns, the Ideal Guild Quiz you see before you was created.
This quiz is designed to identify your likes and dislikes, process them through a database of information collected from numerous guild leaders, and return a set of recommended guilds. It is not perfect, as the process of finding a guild is an inherently subjective personal experience, but it may provide you with insight that you would not have otherwise uncovered.