How to get a breast milk stash going while still breastfeeding?

I would love your ladies tips in how to get a stash (for work and any outings or even donation to fellow mommies) going while still breastfeeding? My girl eats anywhere from 1hr to 2.5hrs depending on time of day. I pump in the morning and get a lot since she usually sleeps for 2.5hrs to 4.5hrs at night, but have no idea how to pump during the day with her feedings being close together.

Also tips on how to increase milk supply? I drink lots of water and drink Mother’s Milk Tea. I’m thinking of taking fenugreek pills to help get more out as well.