These are printed on the site but did not make the vid:
Step 12: Signatures
...should be small and tasteful. Massive graphics plugging something you're selling are a right royal no-no. Text is very much preferable.
Step 13: Avatars
Your profile pic is how people picture you, so choose something good-looking, funny or interesting. Pretty much anything goes, just make sure it isn't ugly or annoying and fits with the tone of the forum.
Step 14: Gravedigging
Old threads are old for a reason, and that reason is that noone's interested in discussing that anymore. Unless you've got an outrageously good reason to do so, leave dead threads to Rest in Peace.
Step 15: Drama
Used properly, The Internet can be a tool for good. If used for overblown, melodramatic weepy Emo nonsense, it's ruined and needs to be scrubbed clean. Learn to relax and take everything in your stride. Noone's on The Internet to get all stressed and angsty, we're all just here for a good time. So leave all your haughty drivel at the door.
Step 16: Smilies
If used sparingly a smiley can emphasise a point: sarcasm comes across extremely poorly in forums almost dangerously so. A quick winky will sort that. Reams and reams of extravagant animated smileys performing all manner of wacky acts are annoying, and are the sort of thing your mum would do, were she able to use a computer.
Step 17: Read the FAQ and Forum Rules
Because they'll tell you how the community there likes people to act. They're there for a reason.