I have always avoided designing anything too technical, like vehicles of any kind because I found it hard to imagine the structure and how it would be put together. I always thought that I needed to think about that so that it would look plausible, but sometimes this makes it difficult to know where to start. I was looking at a Star Wars artbook I have, and noticed this quote by concept artist Marc Gabbana “When I draw [a vehicle], I don’t think about how it’s going to be built. The second you do that, you put a limit on your drawings.”
I found that when I just put my head down and just started thumbnail-ing it wasn’t so hard after all, and even though the designs range from simple to generic to odd it was a good way for me to finally start on something I originally wasn’t comfortable with.