Some very good advice here. Biggest tip I can give is too get back to easier terrain to start off with. Too many people try to learn new skills on terrain that doesn't allow them to relax or concentrate on the new skill or task they are trying to complete.
Try this linear progression of movements.
1. Riding across the hill in a traverse
2. Garland/Twisting board: then start to flatten out your front foot to the toeside(you don't need to press it down all the way to the snow but it should feel like you are starting to roll your weight from your heel to at the least the center of the board) This will cause you to start to get into the fall line.
3. Rotate/spin your feet/hips in the direction you are trying to turn.
4. Once fully in the fall line engage/pressing your toeside edge into the snow.
5. Finish out the turn but finishing your rotation across the hill to slightly up.
To assist please look or refer to the following spatial relation of you board lengthwise(i.e. where the "nose" of it is pointing) on the snow.
1. Across the hill / perpindicular to the fall line.
2. Pointed slighty down the hill/ think 45 degree angle
3. in the fall line or board is pointed straight down the hill
4. Pointed slightly across the hill at a 45 degree angle opposite of #2
5. back across the hill
or can be referred to clock positions is 6 o clock is down the hill
right to left turn visa versa for left to right turn.
1. nine o'clock
2. seven o'clock
3. six o'clock
4. five o'clock
5. three o'clock