Mate
I'd suggest doing as Ram suggested, get a part time job, enough to pay the bills but cocentrate mostly on your phys- don't over do it but train hard so you are ready for basic, being much fitter than the required standard will make basic a hell of a lot easier.
Oh and as per the arrsepedia-
Royal Marines - ARRSEpedia practice being sexually deviant while on the piss.
Don't worry for all the Royals out there, in the modern age alternative lifestyles are all the rage.