Let’s get some actionable constructive criticism in here. Some of the design recommendations are great, but difficult to take action on.
At the least, you should segment the different types of buttons. Colors should be boxed (or do something similar to Kwahn’s mockup).
The gray background which melds into the top bar (time/battery/etc bar) looks pretty bad. Consider making the top bar differently colored, and not using grey for the toolbox.
The toolbox feels “thick”. Try reducing its height and making all the tools use a similar height. Reduces the feel of wasted, ugly space.
The red button thing in the top right looks awful. Is that indicating your current color choice? And is that why the red color on the palette is bigger than the others? Lets combine the two and encircle the current color used on the palette, and remove the right button thing completely. Also, making the red bigger looks…inconsistent. The border should be plenty.
Speaking of the border, the black you’re using is very strong. I think you could go a few shades lighter and not lose the “black” feel.
Hope this is a good starting point for you!