No offense, but a forum dedicated to aikido is probably not going to be as helpful in picking a style of taijiquan or an instructor, as say, one dedicated to the chinese martial arts. You might try:
Or do an online search. There are a ton of sites dedicated to taijiquan.
However, I think the same general kind of qualities you look for in finding and selecting an instructor and dojo in aikido would apply for any martial art. Also, whether you live in a large urban area or a smaller town will probably dictate what kind of choices you will have. I don't think I'd be as concerned about which style to pick as much as finding a good instructor. Best of luck.