Power Pumping

Anyone have advice about power pumping to increase supply?

I am EBF my 3 month old but i just went back to work 3 days a week and need to pump for my mom who's watching her. When I'm breastfeeding, i dont have concerns about my supply because my daughter is gaining weight and has lots of dirt diapers, but i cant seem to keep up with how many oz she's drinking while I'm at work. She usually drinks 14oz between 8:30am-5:30pm but I'm only pumping 10oz during that same time period. I pump 3x for 30minutes each but cant seem to get more than 10oz so i want to start power pumping to increase my supply. Advice?