First off, an admission – this isn't MY post. It's from the fab Chris Brogan, and he's said that it can be reposted as long as he's given credit. Here's the original post: 50 Power Twitter Tips

Rather than just repost his thread, I've picked out my favourite of his tips from each section  – please do read his original post to get all 50!

Intent (Human Artist)

• Don’t read EVERY tweet. It’s perfectly okay. You have permission.
• Promote other people 12x to every 1 self-promotional tweet.
• A lot of @replies shows a lot of humanity/engagement.
• Promote the new/less followed more than the “names.”
• Everyone does it their own way. You’re doing it wrong, too- to someone.

Technical

• Leave 20 characters or more space in each tweet to improve retweeting.
• Make hashtags small and simple. We need room to tweet.
• If software allows you to “post updates to Twitter” as well as to the app, don’t do that. We rarely want to see them.
• If you develop software that pushes updates to Twitter, be VERY explicit how that works.
• Every time you use OAUTH to give apps permission to use your account, you open a potential security hole. Check your permissions monthly.

Business

• Spamming us repeatedly is okay. We just unfollow you.
• Finding people who need what you’re selling trumps advertising to us.
• Your customers might not be on Twitter. Use rapleaf to find them.
• Invite your customers to Twitter, then make it worth it for them.
• Use Twitter as a personalized communication tool, not another blast.
• Just make money and then the boss won’t ask about ROI any more.

Integrated Usage

• Apps like TweetChat.com make following event chats really easy. Put in a hashtag and go.
• Tweeting the content of events is nice, but so is occasionally making a real live connection with the speaker.
• It’s okay to tweet your blog posts, but try asking a question that leads readers into the post.
• Can you invite Twitter followers to your other social platforms, like LinkedIn or Facebook? Sure you can.
• Tweets that point us to photos and/or video and/or music, etc, are always a great way to enhance the experience.

Off-Twitter

• Are your tweets really what you want to show in your sidebar? Doesn’t that direct people away from your site?
• Apps like VisibleTweets.com are neat, but can be very distracting at events.
• Don’t forget to invite people from off-Twitter to follow you on Twitter. Include your actual Twitter ID (I see lots of “follow me on Twitter” with no details).
• Asking questions on Twitter makes for very interesting commentary and opinions for blog posts.
• If your only marketing efforts are on Twitter, start building an email marketing list. Never put your eggs in one basket.
• Start thinking in 120 characters (remember? save 20). Every bit of this advice is tweetable.

As always, fab points from Chris – be sure to visit his original post and let others know about it!