BDSM means a range of things but there are some basic common sense things to keep an eye on.
1 - Communication. Both parties need to discuss what they want to happen and what they think will happen to avoid nasty surprises.
2 - Safe words - very important! The most common are "Yellow" for "back off a little, I need to recover" and "Red" for "all stop, I want to get off this ride". Makes it a lot clearer when the rest of the time you are supposed to say "yes!" to keep going and "no, stop" to keep going...
3 - Keep an escape route on hand. If you are using ropes to tie someone up, have shears / cutters / something on hand to cut the ropes if the knots become hard to undo, the person's wrists swell up or w/ever. Don't use handcuffs / chains that use locks or pressure to hold, use the spring-loaded ones that don't require a trip to the locksmith (or hospital) to remove if you misplace the key.
If you do use key ones, keep a spare key handy!
The main things to remember is "Safe, sane and consensual". It might also pay to have someone (or a couple) with more experience give you some one-on-one "lessons" (not necessarily with intercourse, just chatting at a cafe or something) to give you a broad overview. This may give you more ideas.
Also, it's not essential to go out and buy some expensive purpose-built gear. Most homes have plenty of stuff available to play with.
Edit: And feel free to ask questions! The only stupid question is a question that should have been asked, but wasn't.
