I repainted my landy this summer, they previous owner had done a **** poor job and hadn't lacquered it in time and the paint went off and consequently didnt have a good key so it all peeled off.
After a little research and no prior experience i borrowed a compressor from a mate, bought a £20 spray gun and went to a diy store and bought Rustoleum metal primer, top coat, some white spirit and a variety of sand paper.
Removed all the checkplate and fittings i wanted to keep clean annd went over the whole lot with a electric sander 100grit then 240grit. You dont need to take it back to bare metal infact its easier if you dont just remove all rust/aluminum oxide and flaking paint. Wack on some primer (doenst need to be perfect just needs to be decent coverage, i used grey and a bit of black when i ran out) let it dry for 24hours.
Inspect all the surfaces if you can remove any drips etc just use some 800 paper same for dust/ flys etc the undercoat doesnt have to be completly smooth but if you remove large imperfections you will get a better finish.
Choose your prefered rustoleom paint, this stuff it magic, its an enamel based single pack paint (ie no harnder required) and is used for argicultural machinary (hence all the tractor colours) its a little bit elastic so doesnt split when pannels warp/dent. Its cheap as chips and it self levels (to a degree)
Mix it with white spirit (do not shake, stir or you will get air bubbles) to a consitancy like single cream, its more guesswork than science everyone has their own prefered consitancy for spraying. Spray a coat, leave to dry for an hour spray another, leave 1hr spray another leave for 24, flat down with a 800 paper. Another 3 coats, flat with 1000, another 3 1500 another 3 and you should be done, leave to dry for a decent amount of time finsh off with the highest grade paper you can get (halfords do some 2000 i think) compound it and then wack a few layers of polish on.
The whole thing from start to finish took me a week in my front garden no special equipment needed whole lot cost me no more than £100-150 i have to admit having never done it before i was a bit worred but the beauty is if you do it wrong stick an electric sander over it and start again!!
Here is the result (photo taken after 6months on a dull day if its sunny the think look fantastic!)