I can play pretty loud everything from low G and higher, but anything lower the loudest I can get is about mp-p. How do you increase the volume of lower notes? What do you do embouchure/airwise? Appreciate any suggestions!

This is assuming that you flute is in good playing condition.....One of the big issues with the lower area is tone quality. It takes a lot of muscles to play low notes and it still takes a focused tone. Most professionals practice their scales and long tones daily throughout the entire range.

well said Bilbo, remember that you have to find the notes on flute, they need to be approached, hence the reason to practice long tones...

try starting on a note you can produce well and gradually descend, don't continue until you get a warm focused tone on each note...hold each note for 4-6 counts at 60 on the metronome..do that each day and you will have beautiful low notes...