If the enemy king steps on the same file as his rook pawn, you can trap him there.
1.Kc4 Ka3 2.Rb3+! Ka4 3.Rb5 Ka3 4.Rxa5+ wins.
5. Knight Underpromotion
What if you're on the weaker side, and your opponent threatens mate? Black's situation looks desperate.
1...c1=N+!, and it's a drawn Rook vs Knight ending.
8. Connected Pawns
A rook can even stop connected pawns all by itself--as long as it acts before they both reach the sixth rank.
The secret is to get behind the lead pawn. In this diagram, Rg6 then Rg4! wins.
9. Split Pawns
A lone rook can't stop a king and split pawns unless four or more files separate them.
In the diagram, if Black plays 1...Ke2? or 1...Kg2?, White plays 2.Rxa2! and draws.
With these tricks up your sleeve, you'll win or draw more than your fair share of Rook vs Pawn endings. :)