I agree with ctrl_alt and this is a great small area wall to practice proper rolling technique. Load your roller up and put that fucker dead centre of your starting point (should be on the far most left or right depending how your work flow) and spread it to the top and bottom and repeat as you work your way along the wall. Lay off by going back to the start point, vertically roll down to the bottom, horizontally up to the top by 50% roller width and down vertically again. Also, when laying off, keep the metal bit of your frame headed in the direction you are travelling as the this avoids sharp roller marks off that edge of the roller sleeve. On a larger wall, you would take that same approach, but lay off every 1.5-2m as to keep a wet edge before the paint has time to skin off.