I recently was told that once you find a good solvent mixture for separation on [thin layer chromatography][1] (TLC), you should only use 10% of the more polar solvent (for silica) when you run your column. I tried it and it worked great! 

Since I'd never heard that before, is that a standard rule of thumb, or did I just get lucky?

  [1]: http://en.wikipedia.org/wiki/Thin_layer_chromatography