Post your message only where it belongs. When in doubt, ask the maintainer of a given mailing list whether your alert is appropriate. Do a post-mortem. When the campaign is over, try to derive some lessons for others to use. Even if you're burned out, take a minute right away while the experience is still fresh in mind.
Good guesses are useful too.
Don't mistake e-mail for organizing. An action alert is not an organization. If you want to build a lasting political movement, at some point you'll have to gather people together. The Internet is a useful tool for organizing, but it's just one tool and one medium among many that you will need, and you should evaluate it largely in terms of its contribution to larger organizing goals. Encourage good practices.