Tips for positioning with a High and tilted cervix?

I'm a new cup user and I just bought the new Tampax cup (because that is what is available where I am) to start out with but I'm having a lot of trouble with it. I'm pretty sure I bought the wrong size. I'm having a lot of leaks still, but less as I'm getting better at positioning. So until I can get a new cup, I need help to get the best possible position to get the fewest leaks I can. Tips?