advice

I'd say starting to view forms as shapes, and working from those shapes

Line of action has a good section on still life and basic shapes that you can use and follow along

check out for things like gesture drawing and basic perspective.

gesture drawing will make your poses much more lively and real rather than stiff

perspective will help you with 3D dimensional space.

trying doing exercises of perspective also by drawing them in perspective through various angles and positions, it helps