How to increase flexibility?

I want to be able to go all the way down in my split (I'm probably around 3 inches away). I also want to learn how to do a punch front, back tuck, back handspring, aerial, cartwheel, round off, round off back handspring, layout, pike, front hurdler, full and double full. Any tips or suggestions would be appreciated. Also, which would you rank as in order from easiest to hardest? I REALLY need to work on this for cheerleading.