Walls, skirting and door painting

[MrsQ]

This is my first post, have bought first house and although dad is DIY exoert I want to do things myself (so expect many many stupid questions from me!)

Firstly I am planning on painting doors and skirting boards this weekend. Am I right in thinking I need to sand them down but only so as to 'key' the surface not to remove the existing paint entirely, then undercoat, then gloss?

Secondly, want to paint spare room which has pretty good even surface and is just cream at the mo - do I need to do any preparation or just paint straight over?

Thanks

 

[LJW61]

A light sand for a 'key' , an undercoat then gloss , alternatively 2 coats of satin or eggshell without undercoat.
For walls just sand-down any obvious irregularities- lumps/flakes etc then apply 2 coats (at least) of emulsion..
Buy the best you can afford, proper trade 'branded' such as Crown, Dulux Johnstones etc.
Try to avoid B&Q/Homebase etc 'own' brands no matter how tempting the cheap price!