During early flowering I trim up the bottom "popcorn" to allow for better air circulation, I wouldnt go as drastic as the guy in the photos prior... maybe a qtr of the way up not half way... I believe he could yield more had he left more lower branches even fan leaves. (the lowers you can leave...
and the droopy leaves could be from overwatering and drowning the roots, remember they need pockets of dryness so they can access oxygen in the medium. try adjusting your watering techniques and be sure to add cal/mg to your water if it has a low ppm from the tap.