Looks really good, very clean. An excellent start. Some advice/critisizm.
There are a lot of things that go into having a shaky hand, and a lot of solutions.
First, magnification. I was amazed in college when I started using dissection microscopes (two lenses so you have depth perception) how steady my hand was at the microscopic scale when usually I had a shaky hand when working with small objects. Get some hobby magnifiers and a lot of your shaky hand will go away. You can get headband ones that work pretty well for less than 30$.
Secondly, never hold the mini in your hand when painting details. You are doubling your shake when you do that. Ideally you would use one of those mini-holders, but I typically just put it on the table and hold it in place with one hand. Not perfect, but it helps a lot.
Next your gold: it looks like you are painting gold over a black base. Don't do that. Base the area in brown first, then paint gold over that. Gold needs to be highlighted just like everything else. Try burnished, shining, then shining/mithril for edging.
It looks like you may not be using washes, but just painting up by hand. While you can get excellent effects like this if you are good, for those of us who aren't golden demon painters washes produce better results. For the steel try base (boltgun I'm guessing), badab wash, highlight with base, highlight with silver (mithril). For gold try brown, shining, wash, burnished highlight, burnished mithril edge.
I had a hard time with the glowing green of the Necrons, trying several combinations of dark angels green, goblin green, scorpion green, and white, but never getting a result I was happy with, until finally I hit some advice that really made my greens pop: green should be highlighted with yellow. Yellows are usually very thin, so it still looks green, but a very vibrant green.
So try goblin green, scorpion green, scorpion/yellow highlight on your green 'gems' (if you really want it to pop add goblin/dark angel to the front of that list).
Looking forward to seeing more.
Automatically Appended Next Post: One last thing. I'm guessing you saw the
GW paint job of the overlord with the gold rims and liked it, just like me. It's tough to pull off.

If you inspect their picture closely you may notice they made it look 3d by having a thin black line separate the blue and gold portions and simulated edge highlighting on the 'edges' of the blue and gold areas.
Now just painting a thin black line that perfectly would be tough, certainly beyond my capabilities. I've found some success is first doing the edge in black, then re-doing it, slightly thinner, in gold, leaving a thin line of the black exposed. I've been pretty happy with the effect. It isn't perfect yet (my hand isn't steady enough

), but at least it now looks like the armor itself has a ridge instead of just being painted gold.