As you probably know... improve: make or become better enhance: intensify, increase, or further improve the quality, value, or extent of. Usually, enhance is used when a certain quality is being improved or exagerated. ex. This makeup will enhance your features/ Enhance the effectiveness of your site. While improve is used when you're making something better. Because of their similar definitions sometimes you can use then interchangeably. ex. I'm going to improve my worth ethic/ The prime directive needs improving.

enhance: increase the good qualities of something, make it look better "you can enhance the status, the reputation or the position someone. "Those clothes do nothing to enhance her appearance." improve: to cause something to become better "Her health is gradually improving"

They have similar meanings and can often be interchanged, but not always. It depends on the context. Here is an example to show the difference: Enhance - to intensify an existing quality. It is 'generally' used in positive context, but NOT always. Improvement is always used in a positive context. For example, if I was poor, I might say: I want to get some money to improve my situation. If you changed this sentence and used enhance in place of improve, it would sound strange: I want to get some money to enhance my situation. This gives a completely different meaning. It sounds like you want to continue to be poor or be even poorer! It is important to choose the correct word for the context.