Don't just memorise openings

You can get a long way by memorising openings (and in a lot of trouble if you don't remember them properly). You can probably get a lot further if you memorise your endings as well. Apart from the obvious positions (K+P v K, Lucene, Philador etc) knowing a few of the 'classics' may provide uprising rewards as well. Unlike openings where the transfer of knowledge between disparate variations often does not work, ideas often are transferable between different endgame positions.
Here is an interesting study by Behting (1902) which demonstrates the idea of using mate threats to promote a pawn. The winning idea is to force the Black pawn to c5 and then capture it. At first this looks impossible to do, as Black isn't forced to push the c pawn but through subtle manoeuvring White combines threats against the pawns with the idea of getting the King to e6 and mating with f7!
The main line is 1.Kf3! c6 2.Kf4! c5 3.Ke4 Ke8 4.Kd5 Kd7 5.Kc4! Ke8 6.Kxc5 d3 7.Kd6 Kf7 8.Kd7 and wins!