Growing Your Twitter Followers

I am participating in an 8 week Social Networking/Media  course with SelfGrowth.com (@selfgrowthnow).  The last two sessions have been all about Twitter.  I am actively working on growing my Twitter following.  Some of what I am gaining is:

Twitter does work for brick and mortor businesses
Tweets should be all about value and content and limited on promotion
Engage with Followers
Pariticpate live regularly

Another tool that I am using to build my network on Twitter is:

I also have just started playing with 12seconds.tv, which gives you the ability to create a 12 second video and tweet it. I was amazed to receive a phone call from someone that saw my 12 second video, went to my website and gave a call.

Very cool!!

What tools are you finding effective?