If the paintwork is in sound condition apart from a little peeling here and there, all you need to do is lightly sand to give you a key ( ie ) a rough surface, now this is the important part, buy some good undercoat (white) you don't need primer, crown undercoat is good BUT NOT THE QUICK DRY,this you will find is water based and usless, it drys before you can spread it, for a good finish put three coats on, the first coat you will still see patches of brown, the second will be whiter don't be tempted to stop there give it a third coat and WOW! then buy some crown gloss ONE COAT about £18 per two and half LTs (LARGE) don't be tempted to buy cheap value paint from the big DIY stores or you will fail in producing a good job, and you will have wasted your time and money, you will also need good brushes kept clean at all times after use, a tip: a lot of the brushes they are selling today are not pure bristle they are man made synthetic/nylon go for the brushes that are recomended for varnishing much softer and will give you a smoother finish with less brush marks. you may only need one top coat, but again two will be the wow factor, you will only get a good job if you put the work into it, how i have told you