TRUST YOUR GUT! If there is even one single thing that make you uncomfortable or turns you off about a potential dom, you need to be looking elswhere. There are actually many exptremely educational threads in this forum about this very thing, and I highly reccomend you read them.

True doms vs. play doms:
http://www.bdsmlibrary.com/forums/showthread.php?t=6617

Moving from online to real-life relationships (has good list of red flags to look out for when getting to know a dom online):
http://www.bdsmlibrary.com/forums/showthread.php?t=6759

Excellent thread about how to tell real, caring doms from fake, potentially dangerous doms. Definitely a must-read; the ENTIRE thing:
http://www.bdsmlibrary.com/forums/showthread.php?t=3647

There is a lot of trust involved in a d/s relationship, so make sure you find someone who is interested in and cares about YOU, not just making themselves look good. Happy hunting!
-Phantome