Been a while, but I thought I'd say a few more things that helped with specific levels. Plus some other generic tips
A. Hope that no barricades are at the very ends of tracks, especially ones with big jumps
B. You gradually move faster in later levels
C. Don't lose heart even though every level design is RNG.
D. Practice as often as you can; there are no save checkpoints or continues as there is in JotPK.
1. time jumps with the falling boulders so that you land on top of them, but not if they are on too small tracks to jump off of later; they'll make you lose in a flash
2. the slopes are almost impossible to time jumps accurately with the massive speed boosts
3. The gem sea giant bubbles are easy to dodge in 1.6, but you better hope you don't need them to clear any gaps that will otherwise lead you into other gaps and past vital fruits
4. Slomp is easy to get away from if you don't have to rely on climbing too many sticky upward slopes and dodge too many barricades
5. You really get a noticeable speed boost in the galleon, and you often have to jump at the VERY end of tracks to clear the gaps which get massive at this point, and even worse in later levels.
6. Try to land on the leftmost parts of big purple mushrooms and adjust your timing with where you predict the other purple mushroom will rise, try not to rely on bouncy little purple mushrooms if you can help it. Platforms in general are rather small, so expect to make a LOT of jumps
7. The roller coaster is just a lot of jumps and timing that's muddled by the sharp peaks and valleys in the tracks.
8. Think fast on the speedway. Many tracks are free to jump on, but some are better than others. Be judicious and get as quick a read on the upcoming gaps as possible.
Everything is okay.