How to make your figures/diagrams very impressive?
Your diagram is the first outlook, so, it should be more impressive. you can do all or few of the following things to improve your drawing.
1. Add a rectangular border to your drawing, figure.
2. Give a little shade to this drawing/picture.
3. Make the diagram/figure with a sharp lead pencil.
4. Write caption to the diagram at the end of the figure.
5. Underline the caption.
6. And above all make it with a scale/ruler to give it a fantastic look.