I see you have already gotten some great advice. So i'll just add my two cents here. For me the most important element about a bdsm relationship is trust. Whatever you do, get to know the person you may want to experiment with before you let them take control. Do not just jump right into being tied up and used by someone that you can not trust to respect your hard lines.
Second is that knowledge is power. If you want to know more about this lifestyle then read, read, and read some more. There is a wealth of writing just in this site explaining the ins and outs of bdsm. Just talking to people will not tell you all that you need to know. There is more to learn than any one of us can remember to tell you in one sitting. Check out the forums and gain information before you being playing. This way you can get an idea of what your turn ons are and what your hard lines are(lines you will not cross) Trust me, you will read about things that you've never even heard of and therefore would not have known to tell someone you did or didn't want to do.
Okay well, i've rambled a bit, so i hope this all makes sense. Best of luck.