Learn · Level 2 · first look
Make the top yellow
Ignore where pieces are going; first make every yellow sticker face up. Three algorithms you half-know already.
From Level 1 you know the yellow cross: F R U R' U' F', up to three times. Keep it. The upgrade is what happens to the corners, and it uses the Sune and its mirror twin, the Antisune.
After the yellow cross, look at the top corners. Exactly one yellow sticker facing up, on the front-left? That is the Sune's case: play it and the top face finishes. Exactly one, on the front-right? That is the Antisune's. Any other picture, play a Sune from any angle and you will land in one of those two. A computer search has checked all 62,208 last layers a cube can legally produce: these three algorithms orient every single one, in at most four applications.
Verified by exhaustive search: every reachable last-layer orientation falls to the cross algorithm plus the Sune pair.