I allowed myself to change tag for your pic, asit was too big for the page
now, on to the mini

Paint is where it should be, that's a good start

but, if you want to go beyond table-top level there are few things you could do.
first (of course) is increasing the contrast. I can't stress it enough - deeper shadows, lighter highlights. Exaggerate contrast. Go over the to. Don't be afraid.
some darklining to make shadows and separate different elements (like chain from the body, or bandages) would help.
you could play with colours too, introduce some additional shades and tones. such a mini just asks for it - spots on the rotten skin, blood stains, rust on the axe... glazing is your friend here.
zenithal lighting maybe? again, it would pretty well for this sculpt, with lots of hidden and shadowed places.
finally, base is a bit plain. for gaming it sure is fine, but if you want a showcase piece... see above and maybe introduce additional elements to it to make it more interesting.