Step 1: do not work out how much paint you need.
Step 2: do not prep the walls
Step 3: do not clean/Hoover the floor to remove dust
Step 4: do not wash the skirting board
Step 5: do not mask the edges for a clean line
Step 6: forget that you are not tall enough to reach the top of the wall
Step 7: wear newish clothes
Step 8: forget that you will need more than one big roller
Step 9: don't cover the floor and furniture
Step 10: let your partner in crime paint pictures of male anatomy on the wall
Step 10: let your partner in crime paint pictures of male anatomy on the wall
And when you do all of that save the situation by buying a step ladder and masking tape, being glad that you haven't painted the skirting board and that the emulsion is water based and you can paint over doodles. Clean your hard floor with sugar soap and breathe a sigh of relief that you painted before the carpet was laid.
Then order some more paint.
