Don't be scared!

Don't be scared to talk to whoever you want to talk to. Just don't think about it. If you hear yourself saying that you won't be able to do it, just tell yourself you will either succeed, or not succeed. it's a 50/50 chance of succession. Something that helps me is to clear your head of all doubts and just focus on your goal, that way you will never be scared. If he/she doesn't like you, it's their loss. If you don't know how to talk, then practice elsewhere, so you will be used to talking to girls/boys.