How do I pick good keywords for literature alerts?
One of the biggest problems is that there are, in fact, waaay to many relevant papers coming out; that's because there are lots of articles published each month in many different fields.

The approach I found most useful was threefold:


Set up author-specific alerts for the big names in your field. Read both those articles and the citations. They know the literature and will cite stuff you should be familiar with.
Set up alerts to see when someone cites a seminal paper. In my research, there were certain seminal papers that everyone participating in my tiny subfield would always quote. Find those and set up alerts when someone cites that.
Read the most popular article(s) of the month (most downloaded/shared/read in your journal of choice) to stay on top of interesting stuff that's going on.