I've been attempting to become a display pilot for some time (well since early last year, but circumstances - varying from FMD to the chap teaching me the skills' wife having a kidney transplant, have got in the way somewhat). However, I'm slowly getting there and hope to do a few shows this summer.
There's no money in it. so don't even think about that aspect - the best you'll get is a reasonable contribution to costs. But, a commercial license is not a requirement, a good few hundred hours in whatever you're going to display probably are. There's a CAA publication, CAP403 which covers the strict regulations.
First trick, find an experience display pilot and persuade them to teach you the skills of display flying, planning, rehearsals, etc.
Second trick, do lots and lots of practice.
Third trick, get a CAA display evaluator down, they'll go through your routine, discuss safety issues, watch your display, and eventually write a DA recommendation to the CAA.
Final trick, get yourself insured, and persuade an airshow organiser to give you a go. Expect to start out doing village fetes and small local shows before you get enough of a reputation to start doing any significant shows.
I'm somewhere between 2 and 3 at the moment, but fortunately my display partner / teacher / is vastly more experienced than I am, so I'm personally optimistic about 4.
G