Work on making all your bars the same width. Start by doing the letters on your keyboard, you've tried to distort them to much and you need to take a step back. Don't do that top extension you did on the first sketch to your S, it looks like a 3. Orange is a terrible colour to use to outline in both those sketches. A green would make them pop more. Try looking at a colour wheel when picking colour skeme and pick contrasting colours to the fill colour for outlines. In regards to your 3d, next piece you do put a dot anywhere around your piece about 2-3 inches away from it. Now, any side that is exposed to that draw a 1 inch line towards the dot. All your lines should be pointing at the same point. Don't do what you did in your first sketch with the blue until you are more comfortable with 3d, those lines should also all be going in the same direction though. Keep practicing and go simple!