@csehz Now you’re thinking with proportions! Good work! The sketchfab model looks a little lumpy in places. Try turning down the strength on the smooth brush to help buffer those lumps out. Maybe the tummy is a little large; it looks like it’s the monkey is 2 heads tall total, so the tummy would be roughly 2/3 of a head and the feet are the last 1/3. If you could flatten out the bottom of the feet more, I think that would help to take some height off.
After checking rough proportions again, it looks like it’s about right. Maybe the 3D view is skewing things a little. I still think flattening the bottom of the feet will help. Maybe the belly is too wide? It looks like the widest point in your reference meets with the cheeks. Ears look good, the face looks pretty good, too. Maybe the lower section of the top lip could be pulled out more? Similar thought with the bottom lip. Hands look good. I like the creases separating the different sections; it looks really nice. Great improvement!