Keeping the passion alive in a relationship is very important, and it should be looked at as an adventure. Even if you feel you are a little shy, there are some simple ways to turn on your boyfriend that can really bring you closer together on so many levels.
Remember that men really respond to the visual. Learn to be comfortable with that. You do not have to have a perfect body, or a perfect anything for that matter. Your boyfriend is with you because he is attracted to you. So, the first step is to find comfort in your own sexuality. If you feel sexy and confident, you will look and feel even sexier to him. Wear the clothing and the make-up that makes you feel sexy, and he will respond to you.
Flirt with him. So many times, when we get into relationships that continue for months and years, we forget those little things that got us together in the first place. Try to remember how you flirted when you first met him. Snuggle up to him on the dance floor. Give him a sexy look. Touch him in a suggestive way when you are out together. This can be very subtle, but it really works. Men like attention. Don't overdo it, just give him enough to build things up, so you can be sure to have some heated romance when you get home.
Surprise him by doing something naughty that you have never done before. Variety is very important when it comes to keeping your boyfriend turned on. Maybe go to a nice place for dinner, then whisper in his ear that you are not wearing any panties. This is fine--don't be shy. (As long as you are not exposing yourself inappropriately in public, of course.) This is just between you and him. You will find that the more you open yourself up this way, the more comfortable you will feel when you are really getting intimate. Your boyfriend will really be turned on by the fact that you can "let yourself go" this way.
Try role playing. Welcome him home from work dressed up as the sexy cleaning lady or something of the sort. That may sound silly, but men really do love this sort of thing. And remember, it is just between you and him. If you have been together for a while, you should have a good idea what he may respond to along these lines. Most of the time it is pretty simple. Have fun with it. This can help lower your inhibitions and turn you both on at the same time.
Do not be uncomfortable with watching adult videos. Again, as mentioned in Step 1, men are all about the visual. If you have never done this, it may surprise you how much this might turn you on, as well. This can really open up your sexual relationship. It certainly does not mean you need to do this every time you make love, but it can add some variety and excitement to your sex life, as long as you both agree to give it a try.
Always be open to talking with him about not only what turns him on, but what turns you on, as well. Most men get very excited when they know they are pleasing their woman, as well as themselves.