Feedback
Professional software development isn't just about writing any code to do the job, but more about writing the right code that the buyers of the software demand. There will always be a temptation to save time by making assumptions or to skip the need to have regular meetings with the client so that more time can be invested into writing the code. Although time can be saved from meetings you don't expect to discover new information, it is rare to have meetings with a client where new information isn't discovered – and it is these new pieces of information that can save you many hours from developing features that are no longer required, need alteration, or where their priority has been dropped.
Feedback can be gained using a combination of methods. With projects often suffering from limited time to get the code written, too much time spent on other activities can contribute to deadlines being missed, hence the importance of getting the right balance between time invested in developing...