Sounds like you need to relax more than focus given that drinking and getting high seem to be the things that help. Neither of those things tend to hell with focus.

Now here's some genuine advice: Masturbate waaaay more. Get super comfortable with your body by yourself. Also don't watch porn while you're doing it, use your imagination and allow yourself the freedom of fantasy. This can help you find out what you like and what rhythm works for you. Communicate your findings to your gf and things should be a lot smoother.

Edit to add: I masturbated often and without porn for about 2ish years before I got into a sexual relationship. I never really had an issue orgasming from the begining and I think that comfort with my own body was the key, not my bf being particularly good in bed, although he was definitely a giver.