Don’t build an entire project and leave it until the end to test what you’ve made. Split up the project into chunks, such as a group of related requirements from the project specification and review, implement and test that group tasks exhaustively before moving onto new features. Bugs missed at the start of a project usually are much more difficult to identify and fix later in the project as they are fresher in your mind, so spotting them early will save you a great deal of time and mental effort.
Contributor: Andrew Ward from andrewleeward.com