I use the latest version of textmate for all my Rails development needs and I feel that I\'m under-using the possibilities or this software. I only installed the Ruby on Rails b
I was on the same boat some time ago. My biggest advice would be to reserve some time to learning your tool. It will do wonders to your productivy.
I started installing the GetBundles bundle:
cd ~/Library/Application\ Support/TextMate/Bundles
svn co http://svn.textmate.org/trunk/Review/Bundles/GetBundles.tmbundle/
With it, you can check and find new bundles. Be sure to go through most of the options of each one you install.
Next, try learning some Textmate skills. I'd recommend the Peepcode screencast. It covers Rails related productivy tips and information, and will give you some new ways to develop.
Then, you try reading most Textmate tips you can find on the Internet. There are a few I read from time to time: Textmate Tips, Cool Textmate Tips, Textmate Tips from Macromates, Mactips, Textmate Productivity Tips.
There is a Textmate book, but haven't been able to get into it yet. Should be useful, though.
Lastly, the best way to improve your skills is to practice. I try to come up with small week-length projects to use new tips or to remember features I had forgotten.
Good luck :)