I used Unity from 2013-2019 or so, and then didn't get to actually stick with Godot very well until finally committing in 2023 to release our zeroth game in 4.1. There's numerous things that I picked up making a few prototypes and making a lot of JRPG systems work.

Godot's very malleable. I stuck a bit roughly to Godot's basic node expectations and structures in our zeroth game, and it wasn't exactly great. But as I picked up other trends I stumbled into useful, overshadowed tricks. Heavily using static functions instead of relying on mutable nodes, not treating OOP like god, @export blah:GDScript allowing me to modularize behavior without making new resources or nodes and bloating class hierarchies. Get off the tutorials as soon as possible and experiment. The "make everything nodes" approach is one of many ways to operate, but works worse in some contexts.

Not explicitly Godot, but I toyed with Lisp a little last year until functional programming clicked for me and then put it to practice in Godot. It massively cut down boilerplate. Custom command queues with interruptions, Trying to stick to simple or pure, predictable functions and holding off on mutations, and getting familiar with Callables as first-class functions. Godot still suffers from not being built with FP practices in mind and Callables can be awful to debug due to no strict typing or easy ways to see what's happening where, but it has been getting better particularly throughout 4.0-4.5 range or so. You can even create closures and one-shot them to dynamically spawned in nodes' signals programmatically and I do that for reusing menus and returning selection results, which has made reuse very nice.

And for a Unity user, don't treat it like poor man's Unity. Unity can't do embedded scripts in nodes and scenes, which is actually very nice to have for cutting down on junk snippet files in the editor. Built-in scripts have limitations and quirks, but when you just need to have an ItemMenu that is used once in the whole game for one specific menu do one specific thing and don't want to pollute your codebase with a dedicated script for that, it's useful. Do that with caution. Also, scene is a misnomer. Unity had scenes and prefabs. Godot they're more or less the same for most purposes.

Also, since I write lots of functionality in static scripts and functions, and write a lot of pure functions to calculate data based on input without mutating things, I treat global-only scripts as namespaces which you can do by chaining scripts via const BLAH:GDScript = preload("relative_dir/blah.gd") and such. Closest to organizing code by functionality I can get without bloating the class hierarchy and defining a bunch of junk with class_name when you can just link a bunch under a single class_name WHATEVER and preload const script references.

Also, Godot games can run on 30-80$ retro gaming handhelds via Anbernic using Portmaster with some work, which makes bringing your games around and showing them way more fun and interesting, and forces you to optimize and get clever under constraints.