How to email a professor for a research internship as a high school student?

The title says all! I’ve read some papers about this specific professor that I’m highly interested in… But I’m not sure what to include within my email! What do you guys suggest would be the best way to show my interest and my willingness to contribute? Also, would a subject title of “Research Internship Request” be too rude?

Hi there!

Though I ultimately decided not to pursue a research internship this summer, I did receive quite a few responses from the professors I e-mailed. I included a basic background of myself, highlighting my experience/interest in their specific area of study. The subject title I used was “Internship Request.” This was what I used as a guide:
http://talk.collegeconfidential.com/summer-programs/1063234-how-to-apply-for-independent-research-internships-p1.html

Best of luck!