When to curl lashes: After you have done your shadow and eye liner, but before you apply mascara.
How to curl: Use the eyelash curler by clamping down on your lashes once...don't pump the eyelash curler, there is no need. By clamping once and holding it down a few seconds you will see results, if you want a more dramatic curl clamp down one more time and hold. Repeat this for the other side.
What eyelash curler to use: Shu Uemura Eyelash Curler

This is a $19 product, but it is well worth it. Every makeup artist I know says it is their favorite, and anyone I've met who owns it or has just bought one LOVES it. When I use it on myself with enough mascara I've had people ask me if my lashes are fake. I have wasted time and money on eyelash curlers that didn't do much, so once I found this product I was hooked. The shape of the curler allows you to get close to your eye, the silicone pad in it and the design apply enough pressure so that a curl is created that will hold. Shu Uemura is known for their eyelash curler, and while they have a number of quality products this is what people return to them for the most. You can find it at Sephora, Ulta, Nordstrom or on Amazon.