Top face
Repeat one algorithm (the Sune) from the right angle until the top is one colour.
Beginner layer by layer
A first 2x2 solve needs only two algorithms. Build a face, then turn the layer until each of its sides is one colour; that is the first layer. Hold it on the bottom and repeat the Sune (R U R' U R U2 R') until the top is one colour, turning the top between tries so a corner whose top colour faces you sits at the front left. Then swap the corners that are out of place with the corner swap of the 3x3's beginner method, held with a matching pair at the back.