If you are trying to do a front side switch up, keep your leading ski's tip up in the air to grip it and the back ski tip down. It has a scissor effect to grip the rail and then pop and throw the 180. Same thing for a blind switch up, except this time your front tip is going to be down and your back tip up. Just watch some videos and pause and re watch switch ups to get a good idea on how to do them. Then just practice, practice, practice.
"I don't do drugs to be cool, I do drugs because they are cool." -C.M.