Refrigerate your pie shell for 20-30 minutes before filling it. Use a glass pie pan. Be sure your apples are dry before adding the flour, sugar and spices. To do this, I use a clean dish towel or a wad of paperr towels and stir it around in the bowl of apples with my hand. Let the seasoned apples sit for 15 or 20 minutes, stirring occasionally, before filling the pie. Leave out any juices that have accumulated in the bottom of the apple bowl.
Preheat oven to 400 or 425. Bake at this temperature for 10-15 minutes, then reduce to 350 or 375.
Also, the pie crust recipe makes a difference. Some hold up better than others. My favorite in the Never-Fail Pie Crust (recipe follows).
Never Fail Pie Crust
3 cups all-purpose flour
1 1/4 cups shortening
1 teaspoon salt
1 tablespoon distilled white vinegar
5 tablespoons water
Whisk together the flour and salt. Blend in shortening until texture resembles coarse crumbs. Mix together egg, vinegar, and water. Pour all at once into flour mixture, and mix together until evenly moist. Wrap the dough in plastic wrap or waxed paper and refrigerate for 20 or 30 minutes. Roll dough out on a floured pastry board or between two sheets of wax paper; no extra flour is needed to roll out dough if wax paper is used.