Hello to all dear … designers should I say? Or artists? Okay anyway hello!
I would like to propose you as a first post of drawing a small and simple advice: do not be demoralized, never. What do I mean? The fact of not believing in one's abilities. I myself thought a few years ago that I would never be able to draw well (not that now knows how to do), but I know that over time the results I will get will be more and more satisfying and therefore always better for me. The secret to drawing well or succeeding in most activities is pure and simple training. Two, three drawings a week will make you improve a lot and even in just a couple of months you will see great changes!
But you do not have to stress, basically designing must remain a pleasure, so you do not need to despair to make perfect designs every time, even some simple sketches will help you improve and keep the pace for your business.
If you want a little more concrete advice there are various ways to practice drawing, how to let the hand flow free on the sheet draw random curved lines (to lighten the weight of the hand), but in my opinion the most useful advice I can give you is to observe reality. Observing you learn a lot of things, look at the details, the shadows, the proportions, everything and try to memorize it. Have you ever noticed that curve that makes the forearm? Have you ever noticed that the eyes are in the middle of the head and not in 2/3?
In short, observe and train with serenity, I assure you that the results will be seen and everyone can succeed.
I will probably write some other small article as a guide, perhaps on more specific subjects. However I leave you here two drawings that I did, one in 2014 and the other in 2016, I would say that the difference is obvious!