For either single- or double-crust pie: Trim the dough even with the edge of the pan. Dip fork tines in flour, then press the fork straight onto the crust edge (or diagonally for a herringbone edge) without pressing through the pastry. Continue along the edge of the pastry (rotating the tines 90 degrees for a herringbone edge) and press right next to the first set of marks. Continue around the edge of the pastry (rotating tines back and forth for a herringbone edge).
Expert tip: For a picture-perfect golden-brown crust on a double-crust pie, use an egg wash. Beat 1 egg (or just the yolk) in small bowl. Using a basting or pastry brush, gently brush the mixture onto the crust just before you put the pie in the oven. If you don’t have an egg handy, plain water or milk both work surprisingly well too!