Here are some of the things I overuse:
After a moment
For a moment
Shook his/her/its head
Other words I hate that I use all too often: that, got, gotten, then, but, suddenly, surprize
I try to read things that will improve my own vocabulary, like the works of Gene Wolfe. I especially like the Book of the Long Sun series.
It is good to be able to come up with a unique word or phrase now and again–something you know captures the essence of what you are trying to say exactly. It doesn’t happen all that often for me, but the more words I write (I have probably passed half a million) the more opportunities I have.