Advice for building confidence for talking to guys?

I've found it easy to approach men who i find attractive (both looks & personality) when knowing most likely nothing will happen because they're much older, my teachers, far away relatives, etc. If I know there is someone who is appropriate for me then I get this overwhelming fear and although it is totally illogical i cant seem to get around it. Any ideas on how to make myself a sort of "safety net" so that I can try to get to know some interesting guys similar to how I approach the inaccessible men?