Something I've learned over the years that if you are writing a tutorial for a tool you've written, it pays dividends to actually perform the steps of the tutorial yourself as you write it.
This seems obvious, but often while developing a tool you end up developing a set of test data as you go. Often features or changes you add later can break functionality that you only used early on. It can be tempting to try to plow through writing the tutorial, since you know how all the features work -- why bother actually doing them?
If you actually perform the operations without having any existing data, you can uncover a lot of bugs, or features that don't work particularly well. Lately, I've gone even further: Take your fully developed test data, tear it down, and then build it back up again. This tests both the creation code paths and the destruction code paths.
If nothing else, doing the above saves the embarrassment of releasing a tool to your artists and designers, and the first time the try the most basic of things, it crashes, because you haven't exercised that code path for a week or two. One last regression test is worth the extra effort.