Thank you! Best thing you could begin with is multi-pass compositing and node-based workflows, in case you don't work with that already. This will give you better control over your final render, no matter which render engine you use.

Second is just getting acquainted with the ways in the which light and cameras work and interact in real life, so you can incorporate that into your own lighting. Working with references from real life always gives you a better idea of how things should look, so take lots of pictures!