RERUNNER is a bit more complex than what it seems on the surface. There's more with what you can do with just your basic actions, and some custom levels require you to be a little more creative with their solutions in order to beat or perfect them. You can also break the boundary for what's normally doable using scoring mechanics that are unexplained in the game.
For me, I only figured these out from small tips from the community & the developers, and I wanted to compile all I know here, so this guide serves a list and introductory to many of the ways you can use CommanderVideo's base moveset to your advantage.

Icon Source: https://twitter.com/BencinStudios/status/1699873648989933727

My favorite mechanic, due to being very rhythm game-esque. When you bring up your paddle just before you hit a BEAT block, a more satisfying sound plays & an additional neon green effect is applied to your paddle, signifying you've done a perfect parry.

The timing is about 90 milliseconds, or around 5 frames before you make contact with the block.
You will get a 10% score boost, which is the same amount as a single dance, making this a very useful & viable mechanic for beating high scores since there's no delay between parrying and your next action.

Block or absorbing in the middle of your kick animation cancels it out, allowing you to act freely & much faster compared to letting your kick play out in its entirety.

This is rarely used in custom levels as a way for you to kick awkwardly-spaced obstacles apart from each other. However, this can open up many levels to additional dancing that wouldn't be possible without kick canceling, or letting you blast CORE blocks slightly sooner than what the level recommends you.

No coined term for this yet, but just like sliding onto trampolines, you can maintain a slide while you spring upwards as long as you are holding Down while you press Up. If you let go of Down in mid-air, you can no longer go back in a sliding position again. Used rarely in harder custom levels as a mandatory thing, has no benefit otherwise & you may miss gold if it's in a high spot.

This is very easy for keyboard players, but very hard for controller players since most of the game is binded to the directional pad alone. I recommend binding your control stick (preferably the one that's on the opposite side of your controller) to all the actions your directional pad has for a much easier time with actions that require overlapping inputs.

Easy to see in game but rarely ever used in custom level design is the fact that the duration of your kick doesn't cancel out when jumping or sliding, easing difficulty that on more obscure patterns that would require both fast input and precision otherwise.

Taken from Runner3, you can get one point from kicking a gold bar. This does not scale at all with your difficulty or mode multiplier, you'll just get 1 point every single time. If you notice you getting more points than usual, or your final score being wacky for some reason, this is the reason why.

Impractical, but a pretty funny thing added by the developers. It could be very well viable when leaderboard scores get more and more optimized in the future.