You need to step away from the computer, slow down and focus a lot on your basics.
For example anatomy, there are many many errors in the above figure.
Just for starters he is out of proportion and the limbs are all different sizes.
get an anatomy book! take reference! not just of the figure....whats he on the edge of ? look up lava flows, mountains, cliffs, i know you have the internet cause you posted this piece. use it for more than just painting. there is a virtual library of things out there in the web. There is also one in the forum section if you go to photography.....there is a sub forum of refernce material....very handy.......once you do all this re work this piece and repost it ....savvy?