I actually don't recommend gesture drawing as a starting point tbh. I personally think it's better to start of learning how to accurately copy just using 2d techniques, and also how to draw in perspective using rulers and vanishing points, and once you have a good handle on these things and start to combine them in the same drawing, you can go back to gesture drawing.
I'd recommend Dorien Itens guide on accuracy. It's free or pay what you want. http://www.dorian-iten.com/accuracy/
And Draw a Box for perspective.