I'm thinking of doing one, may do in my spare time.
Basics are :-
preperation is the key, start sanding with a rough sand paper such as 200-400 grader then work up the grades to around 800, until as smooth as possible. Then use PLASTIC filler primer, and then sand down when fully hardened with 1000 grit. Then apply the colour. Doesnt matter how many coats you put on as long as theres a nice even coverage and the colour is accurate compared to the car. Then the laquer. If possible do this on a warm sunny day outside. If this isnt possible use a hairdryer to heat the room or the laquer WILL go cloudy. Start with a dust coat just to seal the paint then put a couple of thick coats on - this is the only way you'll get a smooth finish. If you get runs dont worry, just wait till its fully dry and sand with some fine sandpaper (1200 upwards) and re laquer and it will be as good as new. When fully cured (i'd leave it at least a couple of days) use some scratch x or abrasive polish, this will smooth the finish further. Then wax as normal.
DONT USE HALFORDS PAINT - the colour match is rubbish. Get your paint from someone like mark at autopaint.com, colour match is spot on.