It totally depends on what you look like. First of all, kudos for wanting to turn your boyfriend on! lol! Now as to what will do that, what´s your body´s best feature? If you have great breasts, go for something showing off cleavage. If you have a great ass, go for something skin tight. If you have great legs, get them on display. What´s you best feature and what turns him on the most?
Lately I have this huge thing for women in dresses and cowboy boots. Hell, I'd take you shopping to outfit you in a dress and cowboy boots if you would just have lunch with me after wearing both. But I am a country boy?