Do positions matter?

Talked to a few of my friends and asked what they did to get pregnant. I've heard of so many different positions it makes my head hurt. One in particular was standing on your head after intercourse. Multiple people have said this to me. First of all I am not a gymnast and I'm a bigger girl, so standing on my head is not an option, especially since they say to stay like that for at least 15 mins. I've done the pillow under my lower back and all that also. Are there any other type of positions people have told you about that may help? And did they actually work?