Warning: A Rather long and wordy criticism headed your way.
You've got a start, but this piece could use a lot of refinement. If you are going to be serious about art, I would suggest investing in a nice anatomy book, and studying from it. Currently, the muscle anatomy is off, and the proportions are off. Also, the mountains don't look really realistic in this case, and seem to be a far over-used filler in most runescape pieces. If you must use mountains, study real pictures of mountains. Mountains do not all look like upside down V's. Granted, some do have rather harsh peaks, but there are others that are more rolling, and further more, the peaks are the only part of a mountain that look like an upside down V, the rest of the mountain slopes.
Here are some examples of mountains, do you see how they vary in shape, and how imperfect they are?
123 Finally, this piece is not balanced at all, at least, not yet. You have a character, taking up most of the left half of this piece, while on the right, there is almost nothing there. To counter-act this, add something to the other side, whether it be a copse of trees, or a wagon, the point is, something should be put there to balance this out. Now, Please do not be discouraged. This piece has potential, it just needs to be refined more, that is all.
