The easiest way is to have a relay node. It increases the number of possible routes and is generally good for Tor. Especially if you have a good internet connection.

The second thing is to just use it! I recommend always using it for e.g. researching stuff for online shopping. Tell friends/family to download the apps and explain that it offers real privacy compared to incognito mode.

Get your companie to support it. You'd be surprised how many companies have exit nodes running. And I don't mean only IT companies where some tech guy convinced the boss that they need it for penetration testing - lot of medium sized companies have nodes because the owners ore convinced. The legal status of companies/foundations/clubs/universities are the perfect vehicle to provide exit traffic since no individual human person is liable.

Get other companies to support it. When the Wallstreetjournal recieves enough emails or cn.wsj.com to a tornode make up a big part of their advertising they will ring the bell. Write emails to Tim Cook or Jeff Bezos personally - one day they will learn.

You can even found a club. There are many clubs only for running Tor exit nodes e.g. Zwiebelfreunde e.v. But many are also wider tech associations such as local Java User groups or other tech enthusiasts.