It is sometimes said that lazy people make the best programmers because they tend to solve problems by taking advantage of proven, working solutions that are already in place. Lazy or not, it's often a great idea to reuse work others have done. Before you get started on a project or before you tackle a piece of code, you should see whether someone has already written a custom tag that does what you need. If so, you can just use it in your code and move on to your next task. It's almost like getting the entire ColdFusion developer community to help you write the code for your application.
You can look for custom tags online in a number of places. By far the largest and most popular is the Developer Exchange portion of Macromedia's own Web site, which offers thousands of custom tags for the taking. In many situations, a simple search will reveal that someone else has already solved your problem for you.