I have thought about this before, but especially when sewing the charleston dress: there are certain styles that just fit better for certain body types. No matter how much I love 20s charleston style, I will never look great in it. Then again 50s style suits me a lot better. Well, there are things I will wear anyway, but it is nice to know what really suits you and what to avoid. To help, there's a great collection of videos at Videojug: Videojug - Fashion for your shape
Basically, it's a collection of videos with the tag - fashion for your shape. You can find the best styles and avoid the ones that really don't work. I'm trying to take these as guidelines, not as strict rules, but I think they might help with defining your own style. Also, it's good to look at few different makers of videos. Sometimes the tips disagree a bit, so seeing a few videos gives more idea what's best in general. Also, now that the summer is almost here, they have advice on the best swimsuit styles as well, so if you're updating your swimsuit, take a look at the advice first!
What I realized watching these videos is, that I've noticed lot of the stuff myself while just choosing clothes. Sometimes, when you really like something, though, you might not realize that while it looks amazing on the hanger, it just doesn't look great on you. So, I think I will keep these in mind while planning what to buy/sew/wear. And it will make the decision that much easier.