In my opinion proactive means the person who is Advance active having the ability and will power to finish the work in best and in advance way as compare to other person. You can say a proactive person having a positive thinking. He well know that how he have to perform the given work in limited time. If any work is very hard and challenging may be a person who is not proactive , refused to do, but if the same work is given to proactive person then not only he will definitely do the work but also welcome and admire the hard and challenging work.
He will do the work in such manner so that it avoid the problems from ever rising. Proactive person will Learn Something with taking an interest. You can say he will play with his work while learning new things.Flexibility is a key positive quality of a proactive person. Being proactive means planning and preparing for all possible results.
I think if all the person make his thinking and set up himself as a proactive person then he will never fail in his life , i guaranteed no body can stop him to make his dreams true.