Support people who are providing services priced in Bitcoin.

Educate yourself and lookout for people who might be interested in bitcoin for various reasons. If you find a person, try to introduce them to bitcoin and answer all questions they might have (or point them to good resources) but meet them where they are. Their reasons for interest could be inflation; taxes; financial privacy; financial censorship; borderless, fast, cheap payments; energy buyer of last resort which incentives renewable energy; "fuck the banks"; "what is money?"; ...

Imo, missing education about bitcoin is one of the biggest reasons why most people don't feel chronically short of bitcoin yet.

Three advices.

1. Go to local meetups and communicate with other people. If there is no local meetups, try organizing one (look at https://twentyone.world/).
2. Try to contribute to software projects you use yourself. Even if you are not a software developer, it's still helpful to test code, review documentation, report bugs, etc. There is always not enough people contributing for Bitcoin to grow faster.
3. Support businesses accepting Bitcoin.

spend bitcoin at merchants that support bitcoin and then convert the same amount of fiat money back to bitcoin

Maybe find a merchant where you live using:
https://btcmap.org/

And spend some of your stacks :D

Sell your products or services for bitcoin and stay solvent

zap people, maybe join our crew

Find a way to sell your knowledge or ss for Bitcoin, perhaps arrange meet ups if there aren't any near you

Get involved in My First Bitcoin. Education is greatly needed.

Join the local meetup or start one if it doesn't exist. Help your physical community create a network of like minded bitcoiners that mingle and work together.