Get the book ways of the rifle. Think there's one up for grabs in the for sale section. Top shooters take their time building the stance before executing the release very quickly, the rest mearly rush through building the position and take ages executing the shot and deciding when to release.
Practice practice practice. Then practice some more. Also other peoples techniques wont necessarily work for you. One of the best things you can do is practice in loads of positions. Move hands around, change feet position, elbows, legs bent or straight. There are hundreds of variations you could try. I appreciate it takes a lot of time, but once you've worked out what suits you, they immediately get easier. Then just practice like mad. I ser positionals as potentially easy points because loads of people hate them and barely try.