A pie and tart crust must be strong enough to keep it's shape and hold it's fillings (tarts are taken from their pans before serving).  Besides a flaky pastry crust, there are all different types and recipes. 

Cookie Dough Crust Basics (used for pies and tarts): A cookie crust is much sweeter than a flaky or sweet crust and is also made from a dough mixture. When working with it, it has the tendency to crumble. Usually  the crumbly dough can be sprinkled in the bottom of the pan without rolling. Use your fingers, the bottom of a glass or measuring cup to press the dough into as level as surface as possible. 

Some crusts can be rolled between two sheets of plastic wrap. After rolling, remove the top one and use the bottom sheet as a hammock to transfer the dough into the pan. A half portion of the dough can be rolled between two pieces of plastic wrap to form a smooth crust. You do not need any extra flour when doing so. The edges will crumble, but can be pressed back into place. When pressing on to the sides, I like to use an empty measuring cup. I place my right (left) index finger on the inside of the cup and my thumb on the outside of the pan and press. It works really well. Work around the pan, pressing the dough into place. 

Crumb Crust Basics (used for pies): Crusts can be made from a mixture of crushed cookies or graham crackers, sugar, melted butter and optionally flavorings. 

Other crusts can be made from a mixture of mainly flour, sugar, oats and butter, with some leavening. The Easy Pat-in-the Pan Cherry Pie Recipe is a delicious example of this. 

A graham cracker crust is usually paired with a custard-like pie that needs refrigeration; pastry crust gets soggy in the refrigerator, while graham cracker crust does not. The Key Lime Pie, Pumpkin-Pecan Pie and the Dark Chocolate Cheesecake Recipes all use graham cracker crusts in their recipes. To make, use about two-thirds of the crust mixture to form sides of crust, making sure to form a high rim that stands slightly above the edge of the pie plate. Compact remaining crust mixture evenly on bottom of pie plate; try not to get crust too thick where bottom and sides meet.

Puff Pastry and Phyllo (Filo) Crust Basics (used for tarts): Puff Pastry, frozen from the grocery store or made with homemade dough, can be made into a tart shell. It can be filled with pastry cream and topped with glazed fresh strawberries as in the Strawberry Tart with Pastry Cream Recipe. Puff pastry comes frozen from the grocery store, so thaw in refrigerator several hours or overnight before using. 

Phyllo Dough is paper-thin sheets of dough made from flour, water and a bit of oil.  When these pastry sheets are brushed lightly with melted butter or oil and layered, they can enclosed both sweet and savory fillings. They can be pressed into pie, tart and even muffin pans. 

Whenever you make a recipe using Phyllo dough, I have found that it's best to have a filling that is not juicy, such as in the Apple Phyllo Tart Recipe. The dough has little fat, and moisture can make it soggy. When you work with it, think of working with those colored tissue sheets; they both have the same thickness. You can always patch and piece Phyllo dough, but make sure you always butter in between any layer or patching piece. 

For best results, thaw frozen Phyllo dough overnight in the refrigerator. If thawed at room temperature, the sheets tend to stick together. Phyllo dough dries out quickly and can crack when exposed to air. Keep the stack of Phyllo sheets covered with plastic wrap or a damp cloth, and work quickly as the sheets are removed from the stack. The left-over sheets can be refrozen, as well.