Improve the Documentation: https://www.odoo.com/documentation/latest/contributing/documentation.html

Help improve the code (or bugs in the code): https://github.com/odoo/odoo/blob/master/CONTRIBUTING.md

Odoo Community Association: https://odoo-community.org/page/Contribute

Answer Questions on this Forum: https://www.odoo.com/forum/help-1/faq

Triage GitHub Issues: https://github.com/odoo/odoo/issues

Upload content to YouTube: https://www.youtube.com/results?search_query=odoo 

Create a free hosted Blog and share your work: https://www.odoo.com/start

Create Group Events in your region: https://www.meetup.com/find/?keywords=odoo&source=GROUPS

Follow, like and share Social Media content: 

• Twitter: https://twitter.com/search?q=%23odoo
• LinkedIn: https://www.linkedin.com/search/results/all/?keywords=%23Odoo
• Facebook: https://www.facebook.com/odoo/
• Instagram:https://www.instagram.com/odoo.official
• Pinterest: https://www.pinterest.com/odooapps/
• Reddit: https://www.reddit.com/r/Odoo/
• IRC: #openobject channel at https://webchat.freenode.net/
• Telegram for End Users: https://t.me/odoo_updates
• Telegram for Developers: https://t.me/odoo_developers

Also, talk lots about your experiences with Odoo on your Social Media accounts.

Join a Mailing List Group and contribute to the conversation: https://www.odoo.com/groups

Brand recognition: Ask companies you deal with if the use Odoo yet, suggest it to your friends, 93% of our Users leverage the free options we have: 

• Odoo Community Edition Download Here
• One App FREE Enterprise Edition Create a Free database

      Compare our two editions at https://www.odoo.com/page/editions

Buy (and show off): a Mug, T-Shirt, or pair of Shoes. OUR STORE

Note: Get Mug's for free for trying Odoo and invited others to do so (details during registration) 

Promote our Education Program: 10 months of access, FREE Scale-Up! Game. 

https://www.odoo.com/page/education-program

Play and promote our Scale-Up! Business Game:

• Free with our Education Program
• Free if you are a teacher - https://www.odoo.com/page/scale-up-business-game
• Free to Print yourself

Register for our free Accountant Partner Program: https://www.odoo.com/accounting-firms/register

Become an Odoo Partner: https://www.odoo.com/become-a-partner

Join/Come to our Events and chat with the Community: https://www.odoo.com/events

Work for us: https://www.odoo.com/jobs

Help translate Odoo to another Language: https://github.com/odoo/odoo/wiki/Translations

Create and/or Review Apps: https://apps.odoo.com/apps

Provide a User Review for Odoo:

• https://www.softwareadvice.com/crm/odoo-profile/
• https://www.g2.com/products/odoo-odoo-erp/reviews
• https://www.capterra.com/p/135618/Odoo/
• https://www.trustradius.com/products/odoo/reviews
• https://www.gartner.com/reviews/market/supply-chain-management-others/vendor/odoo/product/odoo
• https://www.betterbuys.com/erp/reviews/odoo/
• https://sourceforge.net/software/product/Odoo/
• https://www.quora.com/What-is-your-review-of-Odoo

Finally, make sure all of your friends and family and colleagues are getting value from their free One App databases (make as many as you like!) - help them discover the features that solve real problems for them!