Big eyes are really beautiful, maybe you should even define them! But if you are not okay with the big eyes, you should use some thing to distract the attention from your eyes, such as bangs, some glasses, more lipstick on your lips in bright (dark) colors. Just something which makes more impression and takes the attention off your eyes.
You WANT smaller eyes? Why? Big eyes are BEAUTIFUL. Big eyes look GORGEOUS on a girl. Not to mention that you're really pretty already (I'm assuming the profile picture is you). If you WANT to, use Syvia's advice (^^^^^), but big eyes are gorgeous. Just saying.