Painting Advice - Bone and Blue for a Bad Painter

I've had a few boxes of old Eldar combat patrols sitting in storage for a couple of years and I am almost ready for a new hobby project.

The core challenge is that, when it comes to "clean" painting, I am a potato-level painter. Death Guard? Awesome. Throw some Agrax Earthshade on top of that slime green armor. Tyranids? Great. Maybe a bit fiddly highlighting all of the scales, but fine. Eldar? Gemstones... man... those gemstones. And smooth armor panels.

So this is a challenge project for me. Any tips on making a bone armor and blue gems / cloth paint scheme work without needing to be a great painter?

Thanks in advance for any help, ideas, or suggestions. I appreciate any good advice.