Terence Tao: Use basic examples to calibrate exponents. This article, for the eventual Tricki, gives many examples of the following basic procedure. In many problems there is a "size" parameter N, and the problem has an "answer" that we believe for some reason behaves like Nk for some constant k. A quick way to find N is to look at "basic examples" (say, random graphs in a graph-theoretic problem).
The interesting thing about this article -- and about the Tricki as a whole, once it finally launches -- is that its organizational principles are not the same as most mathematical exposition. A typical lecture or section of a textbook gives problems with similar statements but not necessarily with similar proofs; the Tricki will group together problems with similar proofs but not necessarily with similar statements.