You don’t need architectural blueprints, but a little planning goes a long way when painting a room! Think about what you want to do and in which order. Paint the entire room or a single feature wall? One colour or multiple? Will you also paint door frames and skirting boards?
Then, try to calculate how much paint you’ll need by looking at the size of the room and how many coats — usually, at least two. A general guide is 1litre per 100 square feet. You’ll thank yourself later when you don’t run out of paint halfway through the job!