RTA Guide/Cruiser Crossing the Rainbow
Noob
Make sure to wait after you land on the falling block to singlejump or you will doublejump and bonk on the other falling block. You can also jumpkick down as a safer strat, but it loses time.
Beginner
For the longjump double wallkick on the falling blocks, delay the longjump a little bit after going over the gap to avoid accidentally double jumping. Then hold directly up after passing the glass box and tap A twice for the wallkicks. Ledgegrabing after the wallkicks sets you up to have the right amount of speed so you can hold right the whole time when you longjump to ledgegrab the next platform.