Place the dough on the floured surface and knead gently to ensure that it has been mixed and is a uniform consistency. Now dust the rolling pin with flour and begin rolling out the dough to a uniform thickness of about 1/8." Use the rim of a cup or glass as a cookie cutter and cut as many circles as possible. You should be able to make between 15 and 20 circles. Remove the rest of the dough around the cut circles, and repeat the process of rolling it out and cutting circles. Alternatively, you may simply ball up the excess dough and wrap in cling film. The excess dough can be stored in the refrigerator for a day or two or in the freezer for a week or two. It is now time to fill the ravioli. Remove the filling from the refrigerator. Place about a tablespoon of the filling in the center of each circle. Do not overfill the ravioli or they will burst when they are cooking.

Moisten your fingers with water before folding each circle in...

With moist fingertips, the dough will seal nicely in a half-circle. Pinch the sides of each half-circle to seal. Now dump a small pile of flour onto the working surface and coat each piece of ravioli in the flour before adding the finishing touch: using a fork to seal the edges of the ravioli. The fork marks ensure the seal and make the ravioli look professional. Dust off excess flour and now the ravioli is ready to be cooked.
Cooking the ravioli is easy but make sure to remove them from the boiling water as soon as they start floating to the surface. Once they float, the ravioli are done cooking. If they stay inside the boiling water too long, the ravioli will fall apart. Serve the ravioli immediately, topped by any sauce. With ricotta-filled ravioli, a tomato-based sauce works particularly well.

Reference

"How to Make Ravioli." Retrieved online: http://www.wikihow.com/Make-Ravioli