Need Help Progessing

I pretty much just open the game catch some average pokémon and then evolve whatever pokemon I have that are 3 stars. I barely use any stardust so I have like 700k saved and I don’t even know when to use it lol.

Just looking for guidance on how to progress to getting better pokémon with good stats and cp, i don’t really know how to improve directly.

Thanks for any help!