There are skills and sensibilities required to become a good designer, but a good part of it is just an insistence in not settling for the first solution that comes to mind.
If you have something in your mind, go ahead and draw it. If you don't, find references and adapt them to your case. Pick an aspect of what you drew and think of an alternative solution for it. Draw that too.
Once you’ve repeated this process enough times, fewer and fewer of your iterations will be bad. You'll have a bunch of designs to choose from, combine ideas from, and ultimately arrive at a few options to test with end users, or at a final design you are happy with.