Cool man, glad I could help.
I actually used to have little to no artistic background about a year ago as well, so I know the struggles of visualising advice. Further, when I make edits I try to always just touch on only a few things so that people don't get overloaded with new information. You specifically asked for shading and colours, so that's what I focused on.
As far as tips/tricks go... haha. Yeah, I really wish there was an easy way to just read a tutorial and suddenly be good.
But alas no, there is no cheat code. You can definitely learn a thing or two, and it won't hurt to read up on things, but you actually need to just wake your brain up with ritualistic practice to take art to the next level.
How
I achieved this was through my value studies and subsequent thumbnail studies. I also do a lot of sketching and I make of edits of others' pixel art here on Pixelation to fix small things like poor clusters.
What I can give you is some cheat sheet stuff to read that should stick in your mind and help out so you know what to look for when you're practicing. This forum's Arne made
an art tutorial that is actually just amazing. I used to use this, and it's useful for a lot of things, but you will need to put all of these concepts into actual practice and observe them in real life in order for it to sink in.
Then there are a million pixel art tutorials out there. Look up on stuff like banding, noise, pillow shading and palettes. Cure made
a nice tutorial over on PixelJoint that covers a lot.
But more importantly, and above all else, make sure you're enjoying yourself when you do your art and never be too harsh on yourself.