To see what is trending in fashion and beauty you can read your favorite blog or style magazine. Or, if you are curious to see what people are actually buying (not what fashion editors or simply talking about, but what is actually selling) you can go straight to the store -- the Amazon store that is.
I love browsing their Top Sellers section. I find face lotions and curling irons I never knew existed. And because they are massively popular (which usually means good review) I know just about every single one of them is a safe bet. So far this strategy hasn't done me wrong.