Masturbation tips please

I'm 21 and have been secually active since 15 and this is embarassing but I still don't know how to masturbate i mean i wanna enjoy myself and what im trying to do is to think/read/watch something that would turn me on and make me wet but when im trying to touch myself id enjoy it for like 2 minutes and im dry again. i know all that g spot and clit thing but i just dont seem to enjoy it and i think im just doing it wrong any tips?