The biggest trick in this level is causing a sprite overload by creating a bunch of stars with a big egg. This can despawn the bullet bill launchers, allowing you to skip ground pounding the first set of posts. To perform this trick, fire a large egg as shown in the picture. Make sure you have 4+ eggs (of any size) on Yoshi, as more eggs makes the despawn easier.Jumping onto this platform (as opposed to fluttering over it) seems to make the despawn easier (possibly by ensuring all of the stars are on-screen when the bullet launchers are scrolling on screen). The whole process illustrated:
Falling rock room
blabla living the dream is 100 frames faster
wait strat is 40 frames faster
TODO: Actual descriptions of different strats and how to execute them
This is the first level where a red coin duplication saves a decent amount of time. An easy coin to dupe is the from flyguy above the fat shyguy just after the set of 3 flyguys in a row. Be sure if doing a forward spit to land on the ground, or you might spit him into another enemy, which ruins the trick.
The duplicated red coin means you can skip the red coin in the giant post. To acquire the two red coins in the enclosure by the giant post, simply ground pound from the other side.
The video below does not contain the duplication trick, but has a good route for the rest of the level.