I have just moved into a new house and want to paint my very blue room with a nice light pink/blush. I know I will have to prime my walls as they are going lighter, however my question is do I need to do my walls or glossing first? There is a skirting board, picture rail, door and white shelf. It’s already glossed, but I presume I can roughly sand and re-gloss? But what do I do first?