Pie crusts that will be filled after baking present a challenge, especially to inexperienced bakers. Baking an unfilled shell -- also called "blind baking" -- has two major pitfalls. One is the dough's tendency to puff as it's baked, which can be countered in several ways after the dough is made. The other is the likelihood of the shell shrinking as it bakes, which is more difficult to correct because it's caused by the flour's naturally occurring strands of gluten.
Mix your crust using the lowest-gluten flour available. All-purpose flour is better than bread flour, and pastry flour is better than all-purpose. If all you have is all-purpose flour, remove 1 to 2 tablespoons of flour from each cup you use and replace it with cornstarch.
Chill your ingredients, and use ice-cold water to make the dough. Gluten forms more rapidly when the dough is warm, so using cold ingredients earns you some margin for error.
Mix the dough by hand until it just barely comes together. Overmixing the dough, especially after you've added water, is a sure-fire way to enhance gluten development.
Rest the dough for at least 20 minutes after it's mixed, after it's rolled and again after it's put in your pie pan. Ideally, chill it in the refrigerator during each rest period. This helps the gluten strands relax, minimizing the risk of shrinkage.
Dock the dough by piercing it in several places with the tines of a fork. This primarily helps keep the dough from puffing, but it also severs some of the dough's gluten strands, just as a needle-type tenderizer severs tough muscle tissues in cheap steaks.
Line your pie shell with parchment paper or foil, then fill it with pie weights or dried beans. The weighted paper supports the sides of the dough, pressing them against the pan and making it harder for the dough to shrink down the side of the pan.
Press the edges of your dough to the lip of the pie pan, and gently tuck the dough around the lip of the pan so at least 1/16 of an inch is sealed to the underside. This helps hold the dough in place as it bakes, minimizing shrinkage. When the shell has finished baking, you can easily brush off the thin strip of baked-on dough, leaving the pie shell with a smooth and finished appearance.