Use a different razor to shave your vulva than the one you use for your pits and legs.
This may seem like common sense to some of you, but it never occurred to me. Thus, in the past, I have almost always gotten BV after shaving because bacteria got transferred to places where it shouldn't have gone. Thought I'd let you know so you can learn from my mistakes. :P
Also, what is the most vagina-friendly soap? The hot weather fosters sweat and I like to be able to use a little bit of soap on my inner thighs and vulva. What is something I can purchase that won't cause irritation if a little bit of it happens to migrate internally?