I have started a guide for hobbyists starting out showcasing their work online.
The first part is more about "thinking";
A guide to hobby & social media - The Meta (Part 1) Imperial Guard Blog
The second gets you up and running on Twitter as well as giving advice on gaining followers;
A guide to hobby & social media - Twitter (Part 2) Imperial Guard Blog
I have more to come and would really like to hear your feedback and comments.