there are all kinds of things people add and variations on ratios, but the classic, traditional short crust recipe is difficult to top:
3:2:1 - meaning 3 parts flour, 2 parts shortening, 1 part water
i use butter. i also find that you can increase the ratio of flour a bit and perhaps decrease the water a bit, but i never measure the water. i just eyeball it. keep everything well chilled, don't cut up the shortening too small and don't overwork the dough. starting off the first 5 or 10 minutes or so at 400 degrees and then reducing to 350 will help crisp up the lower crust to some extent, too.
also, do a search on pie crusts in this forum. there are many threads with plenty of do's & don'ts.