heres some tips

watch sunkirs agdq run:

in a wide open area in the game (such as the open water by the start in make the moon), boost and then start alternating slight left and right turns (example here, but it's something you probably want to do on every single boost), to convince yourself that you keep your increased speed longer than if you just hold forwards. we call that effect snaking (borrowed from racing games i think) and it's by far the most important movement tech. it's not something you should worry about doing often as you're learning but i think it's good to be aware of it and try to get used to it during longer, easier boosts.

if you try to learn a level route from a record time, its not gonna go well, since a record only gives one small glimpse into how a stage plays out. it'll be much easier to understand a level from a slower time (from a run on the leaderboards or one of my/sunkirs older pbs in twitch vods).

the most important part of learning a stage is knowing the "size bottlenecks" (there's a list at the end), which are objects that it's possible to be too small for, if you miss too much leading up to them. being too small for an object is the only thing that can go wrong route-wise, so knowing where that can happen makes it possible to plan ahead: if you know you're too small you can play cautiously to catch back up, and if you're big you can boost past stuff you might not need.

to start though, just try and follow along with someone else's run, and if you're too small for something, stop and try to figure out what you missed. by keeping track of your size through the whole level, you can get a sense of the objects that are more important and those that aren't.

until you can get a ~40 minute time, boosting is probably going to be slower than not boosting in any given situation. it makes you go unplayably fast, so unless you have a very concrete plan of how you're going to use all that speed in advance, you're probably fucking yourself in the ass

size bottleneck list: https://docs.google.com/document/d/1zKOY0ErE3R2CIFQVd9e2vZm4yWKjj4g7-8HFQXAO6zg/edit

note: some bottlenecks are denoted "hard" in the list, which means that any extra size leading up to them is a waste of time (trivial examples of hard bottlenecks are objects you end a stage on). once you're comfortable consistently being big enough for a hard bottleneck, you can try to start skipping objects that would put you over the bottleneck's pickup size. that's the final stage of optimisation though, and not something worth worrying about until you're able to feel the katamari in your bones

it's also worth noting that it's very unlikely the existing routes are optimal! they've seen quite a few tweaks over the years and i'm sure there's all kinds of stuff you can squeeze out if you try hard enough. every game with a small community is going to have holes in the route because there's fewer people to question conventional wisdom.