One thing I have found useful is to search on the author of a paper you found especially interesting or useful. I have found a lot of related, but slightly different papers that way. That can help you get a slightly wider view of a subject, but it is even more useful when you are exploring a field and are not yet sure of the most helpful keywords.
I have a copy of Johnson-Laird and Miller's Language and Perception; searching on Johnson-Laird's name I found a really interesting short paper from the 1970s about modal connectives in natural language, for an example.
I'd like to get better at doing literature searches. Luke has written a bit about this, but I still have lots of questions.
I've mostly been using Google Scholar; it seems OK, but not stellar. What other tools are useful and for what? Added: is there a good way to find papers that cite a many of a set of papers (the idea being that if I find a number of relevant papers, I want to see if there's a review which covers them)?
How do you look specifically for review papers and/or books? For example, I'm interested in cognitive skill acquisition and I've found a review paper from 1996 but I'd like to find recent review papers on the same or closely related topics and haven't had any luck. Are there specific keywords or phrase permutations that often help? Is searching just the papers that cite an older paper useful? Is searching the same journal useful?
How do you search for criticism? Lets say I've found a paper that uses a particular method or theory but I want to know whether there are significant criticisms. Are there phrases that are often associated criticism papers?
Are there any activities that are especially good for practicing literature searches?