Opinions needed

I am currently working on improving my coloring skills, and therefore have a need of sketches. Because I haven't got any sketches (yet) and I wanted to do something, I decided to do a trace of this picture:



I'm still working on it, but I've finished the stairs already, which turned out like this:



Please tell me what you think and how I can improve it. Critism is always welcome as long as it's constructive!

you need some more detail cracks in them but depending on the person that can come now or towards the end....but i do like the shadowing: could blend s a bit better, but that comes with the details cracks

Good luck with it!