What I found that helped me is I started with drawing things in really life. Just quick sketches to help you get the hang of it. It helps you realize what you need to shade, what lines put off what effect in your drawing, etc. Then just draw whats in your imagination. Its probly gonna look bad, your probly gonna hate it, but you have to start somewhere. The most important thing is practice practice practice. And make sure your drawing what you want. Since youll probly need practice it will help to draw what you want to stay motivated. This is just my advice, others might have better advice as they are better artists. But this is what helped me learn the most.