The cross

The cross is the four edges of one colour placed around their centre, each also matching the side centres. Every cross can be solved in at most 8 moves; good solvers plan all of it in the 15 seconds of inspection and execute it on the bottom, so they can look for the first F2L pair while turning.
A solved white cross on the D face (white bottom, yellow top); the rest is unsolved.
R U R' U F' U' F U2 L' U L
The daisy: the beginner's cross. The white edges sit around the yellow centre; each is turned down onto its centre with a half turn.
F2 B2 R2 L2
  • •
    Solve it on the bottom, not the top: you see the F2L pieces sooner.
  • •
    Plan the two hardest edges first; the last two often fall in with the moves you need anyway.
  • •
    Colour neutrality (picking whichever colour's cross is easiest) saves moves once you are comfortable with more than one colour.
  • •
    An X-cross solves the cross and an F2L pair together: a typical step for advanced inspection.