Others (mostly Robert Curlette) have written extensive guides and examples for SDL Tridion GUI Extensions, specifically covering the entire setup.
In addition to the API docs, be sure to check out some additional examples from the community.
- Coding Guidelines for the SDL Tridion 2011 PowerTools with some Anguilla examples
- Snippets on the Tridion Cookbook
In case you’re also looking for Core Service examples, check out a Core Service client example on Yet Another Tridion Blog.
Sometimes I forget that although we have much more Tridion information online, sometimes it's missing a curated touch and context. Have any other useful guides or examples you'd like to share? Leave a comment or better yet, share your thoughts, insights, or examples.