For information about rocks you can also have a look at the rock thread here on polycount and read what tools they use to get that rock look like rock :). Keep up the work. Rock thread
I am not much of a position to give advice but I agree with PyrZern, the golem on the concept looks like it was made of rock, the body of your golem looks very organic, and the rock on his arms is a bit out of place "material" wise from the rest of him. *for high details, have you look into HD geometry?…
For being fairly new to zbrush you have done a pretty good job capturing the large form and details based on the concept. At quick glance my advice would be to look over the model from all sides and see if there can be any improvement to the character's silhouette. You can also push the small details way further, for…
When you are working from a concept that only gives you one perspective and limited information, its up to you to gather other references to fill in the information. in your first character you should have gathered reference images of rocks and their textures, of creatures with similar proportions or characteristics. his…
A few things I think you should improve. 1. Presentation. Right now it's hard to see anything there. Well lit object + multiple angles will help a lot. Big big render is also normal. 2. Material definition. Is that Golem made of rock ? The concept seems so. Yours, not so much. The armors and the cloths on the dude doesn't…