It's Friday again. On Twitter, that means that it's the beginning of another #FollowFriday - one of Twitter's all-time hottest hashtags and one of the microblogging platform's best cross-promotion tools. Never experienced one yet? Here's how it works. On Friday, active twitterers get on and send out some Tweets where they list (using @reply syntax) the people that they think their Twitter followers might be interested in.

It's a simple concept, but it has a pretty powerful effect. If you produce good content during the week, you're likely to end up on a #FollowFriday list, and that means that a lot of people are going to be aware of you who weren't before. Likewise, if you do a good #FollowFriday, it might get picked up and retweeted to other people's followers, thus increasing your own exposure as well. The question then, is how to do a good #FollowFriday.

How to do a Good #FollowFriday

1) Don't Wait Until Friday to Start Your #FollowFriday List!

Were you one of those people who started work Thursday night for a thesis due Friday morning? If so, now is the time to unlearn that habit. Unless you want your #FollowFriday to consist of pouring over a week's worth of Tweets, trying to remember which ones were actually worth mentioning, you should start a list on Saturday and begin collecting usernames for the upcoming #FollowFriday.

2) Get Topical with Your #FollowFriday List

Instead of just Tweeting a huge list of @usernames, consider organizing them into a topic-system to make them (and your #FollowFriday in general) more relevant to your followers. Try something like @ActionChick's #FollowFriday list - I was retweeted once on her "People Suspect of Humor" list and got dozens of new followers over just a few minutes!

3) Consider Pre-Tweeting Your #FollowFriday List

If you're going to be doing a lot of #FollowFriday posts, it might be a good idea to schedule them ahead of time (just in case you forget what day of the week it is). Use a service like TweetLater to automatically post your #FollowFriday list to your Twitter feed, whether you're online or not!

4) Don't forget to say "Thank You" When You Get a #FollowFriday Recommendation

If you get a #FollowFriday bump, make sure to say "thank you" PUBLICLY to the people who bumped. A good, if generic format is "@username1 @username2 Thanks for the #FollowFriday!" Some people like to #FollowFriday back the people who #FollowFriday them - that works too, but make sure that person is actually worth being followed or you might lose some credibility in the eyes of your followers!

5) Use the #FollowFriday and #FF hashtags religiously.

#FollowFridays are always tagged with either #FollowFriday or #FF - and there are even Twitter web applications out there to aggregate #FollowFriday posts into an aggregate format like FollowFridays.Com People will still see them if you don't put in the hashtags, but if you do, they'll know exactly what's up without having to ask.

And there you go! Now it's up to you to start finding people interesting enough to want to recommend to your friends - and that's a topic of discussion for another day. Have a good #FollowFriday, Tweeple!