The most important way to help make euclid better is by using it frequently and filing detailed bug reports when you find issues.
You might also consider joining the mailing list (it's low volume) so you can participate in discussions about the future of euclid-wm (as well as have a chance to be notified of major updates or new releases).
If you think this is a promising project and you can write C, I'm always ready to accept good patches (althuogh it might help for you to be in contact via the mailing list first so you can coordinate with the people already working on the project).
This site is optimized for w3m.