When you're low time, it's a good idea to talk to ATC rather than just listen out. They might identify you in order to ease their own co-ordination, and this means they will be able to warn you if you about to infringe anything (controlled airspace, active Danger Area etc) plus if you have a problem of any sort (engine failure, uncertain of position etc) they'll have your position and be there to help rather than you having to call 121.5.