Your main problem is that you are currently focusing on getting detail in your stuff to make it beautiful.
You are trying to add detail by using dither everywhere. however this leads to a very grainy and not really detailled impression.
All the detail won't help if the base of the drawing isn't well established.
What decroded was talking about was that you have to fix your contrasts.
Focus exactly on what happens between step 1 and 2.
Observe what happens with the wall and what happens with the ground.
Also observe the relationship of the changes in the "big image" - focus on the whole scene while you are looking at it.
If you get a better impression through this, you can focus on step 3 (which is basically adding detail).

this means for you:
1) get rid of all details
2) focus on getting your contrast rights that everything reads good and stands apart
3) add detail, while keeping the overall impression you established in step 2