How can I dress more girly?

I've always been told I act girly, but don't dress like it. I'm attracted to skirts, pastel colors, and all those girly stuff, but I've dressed like a tom-boy all my life. So I'm afraid if I change the way I dress, people will think I'm just doing it to be like all the popular girls at school. How can I dress more girly, without making it look like I'm trying too hard?