Anywhere!
This is where the ‘choose your own painting adventure’ kicks in. Some people like to start with their favourite number, some with their favourite colour. Some start in the middle of the canvas, or work their way from the top down, left to right, or right to left. Some start with the lightest colours first, and work their way through to the darkest ones.
HOWEVER you choose to get the painting done, here’s our #1 pro-tip: don't rub your wrists/hands in wet paint. You run the risk of dragging it across the canvas into other areas...which can make for an unintentional blended mess.
Be extra careful of that - and otherwise complete your painting in whatever order makes you happy!