how do I start out writing a essay on the advantages of being in a relationship

Answer 1

What do you plan to say in your paper?

The introduction is the last thing you write -- and only after you've at least outlined the points you want to make in your essay.

Answer 2

Here are two excellent sites on essay writing.

http://lklivingston.tripod.com/essay/

http://essayinfo.com/essays/5-paragraph_essay.php