Splits are essential to any ballerina. By achieving a full split you can maximize your leaps and boost your extension but those of us that aren't born with the body of a noodle will have a bit of a tougher time accomplishing this goal. It takes a lot of time and effort but increasing your flexibility is possible for anyone. When it comes to practicing splits I have four steps:
Hold: Once you find a position that is clearly giving you a stretch without hurting you, hold it. Try to relax your muscles as much as possible while maintaining that exact position for 60-90 seconds.
Breathe: Breathing will help your muscles relax into the position. With each exhale you should feel the stretch become easier and easier. Try to keep a steady pace. (ex. Take three counts to inhale and three counts to exhale)
Stop: After performing the stretch from a minute to a minute and a half, ease your way out of the split. Be careful not to jerk yourself out of it as it may cause pain.
(If you're flexible enough, you can continue with the steps above but put your front leg up onto a bag, pillow or chair to increase the stretch.)