How to get the splits and over splits?

Ok, i have my right split and right over split(still improving, not 270 degrees but more than 180 at least). My left split is.... okay, but sometimes when i do it, i feel like the skin under my left knee is tearing. But i have the left split(no oversplit though. i know, i suck :|). What i absolutely do not have is the middle split. I cant open up my legs!! When i attempt to do it, i feel like my legs are about to get mangled off. IT HURTS SO BAD. I need to get flexible as im in figure skating and i want to do beautiful spirals and pretty spin positions. any advice please? thanks!