Warhammer 40k

I think the overall armor look could be tightened up, potentially in the next guy. With a white or light grey prime, a basecoat that's a hair darker than the intended bone color can be hand painted on (you can play with adding a tiny amount of brown to the bone paint to mix up your own color if you don't want to buy new shades of bone paint) and then a brown wash that's been diluted with contrast medium on it to darken the recesses. While it's wet you can mop up the wash from the flat spots. Optionally add full strength wash to the really obvious recesses once it's dry. Then pick out raised areas with the bone color to brighten it up. Sounds like a lot but it's relatively straight forward and scalable to be doing with multiple figures at once. As always I advocate some kind of painting stand to keep hands off of in progress minis, I personally often use plastic bottle caps and blue tack.

I'd put some full strength wash around the eye area and then paint the lenses in carefully after it dries. The contrast from dark wash to bright lens will help it pop.

With the weapon, black wash lined into the recesses of both the red and metal areas will deepen them. The red areas can get a highlight with a little red mixed with orange on the corners. If you overdo it, you can just go over areas with pure red again until you find a good look.

Similarly the red eagle can get picked out on the wings with a little red orange to give the feathers some shape.

I'd start with washes to add shading the metal work. Talent in a can.