Hey and welcome!
i’ve been working on mobile for most of my career so I can share some things i’ve found. Generally it’s not that limiting now especially with how powerful a lot of mobile devices are. You probably want to avoid any depth fade and refraction as a general rule. I would also say go all out first and profile and then see where you can cut back. Try and share a lot of textures and pay attention to memory. A big issue with mobile games is usually memory so getting a lot of reuse out of textures you’re making is helpful
As far as shaders go you can get a lot out of some simple panning textures along with some distortion. There are also a lot of great ways to use meshes for vfx.
Some talks that were really helpful for me are:
I would also search these forums for things like blend add. There’s a lot of great resources on here already especially simple tricks that are broken down on Shannon’s thread. I’ll try and answer any questions I can though.