>>5940665I'm not very good at it yet but I thought the NMA course by Bill Perkins was a good intro. He essentially makes you draw clothing as gesture for his courses. It reminded me a bit of the FORCE gesture drawing idea.
From there I tried to do more finished drawings from reference. I would usually draw the body underneath then the clothes on top.
After I felt more comfortable with that I would draw a figure from reference then clothe it using an outfit I found would be common in work I would do. In my case it was suits, streetwear etc. At first these wouldn't be as finished as the referenced ones but as I got more comfortable they became more finished.
Then I tried drawing own poses and clothing them.
Good references are pinterest(look for ones that are more static so you can get comfortable with the "frame" of the clothing first) then try some in movement.
Other good references are fashion websites and lookbooks. For example if you like Lolita dresses, Lolita dress manufacturers often have photoshoots of the model in a variety of poses as well as close ups.
White and bright color reference are your best friend when starting. For example black jeans were a bad idea for me to start from since I couldn't see the folds very well. But blue jeans made it much easier.
Sorry for rambling. I hope it helps somewhat.