How can I show my potential in my mail to the professors? I am hoping to continue my masters in machine learning or data mining. So as a part of the process I am mailing to professors. I have a decent GPA and GRE score. I have research experience in these fields but no publication. I am not an extraordinary student but a motivated one. If any professor see my profile they may find it very ordinary. How can I ensure him that I will do my best. I know that knowing the research works of the professors will help you to get a professor's attention. Is it natural to grasp his research work completely? Though the track might be same, but the level of research is more deep than my previous experience. Is there any way to show him I am worthy? 

I am not sure whether this type of question is appropriate for this forum. But hope that someone will enlighten me.
Another way to get the attention of the professor is a recommendation email or phone call from your bachelor advisor. This shows you're so worthy for your advisor that he takes time to recommend you.

Note: In case the professor does not already know you, it might be somewhat hard to get his/her attention just by mail as they receive a number of such mails every day.