They are not as hard as they first seem.
Just practice them a little, you'll eventually be able to guess the patterns the game is throwing at you. Mind you I didn't say you need to memorize the level, just the possible patterns. If you manage to do that you can clear any stage the game has.
- Try to never stay in the center too long, you'll likely get hit by a bomb
- Jump left and right, don't run left and right
- If you keep tapping the direction of the wall you're in, you'll stay stable in the same place
- Each section has 3x the required amount of rings, don't get discouraged if you miss a line of ring at the start of a pattern.
- Don't worry too much about having all the emeralds on the first playthrough. You can replay green grove and go for the missing emeralds quite easily on a cleared savegame