I stumbled on several ideas from Google labs recently. You can see them all by clicking here.
Two ideas stood out (in my opinion). First was the left hand search filter. This gave a list of suggestions to filter down the list from your keyword, try one of these:
The second Idea was to add a drop down list of suggestions as you type – the same goal as above and I think I prefer the first option but I quite like it this way as well. When you get to the search page press space and select the ‘teach’ option.