She know what she wants

Checking the last entry in the diary first, you find that you're "...cute, but a bit stiff? Going out on a dinner and movie with him tomorrow. Old fashioned? More on that tomorrow, need some sleep now. I just hope, though there's little chance, that he's different from the others. I think I know what I want."

She think she know what she wants? That cryptical line turn out to appear at the end of several entries the last year or so. Every entry that involve a guy, actually... and a few girls as well...? Every person she's gone out with?
As you know you won't have much time, you browse the pages as fast as possible, trying to bind all the clues together.

It seems like if Sarah has been even more active in dating than you thought. Every week there's at least one or two new persons to catch her interest, both boys and girls. Most of the time it just seem to fade out as "Another friend that I can talk to once in a while.", and sometimes as "Just a waste of time." or "Just another fool I don't need to speak to again."

Most of the people appearing in the book you've never met or heard of, but there's also a whole lot of people that you do know of.
You did know she had dated "the school hunk" (yet another idiot), but had no idea she had also gone out with "the school beauty queen" (who would probably have gone crazy if she knew Sarah actually considered her a "target". Even more so if she knew she had been dumped, especially with the line "Just a waste of time." as the only note in Sarahs diary!
Another "waste of time" was apparently "the class swot"... So she seem to have dated not just those with good looks, but just about anyone she would find interesting...?

All of those people have very different personalities and ways of approach. Yet none of them seem to have given Sarah the right first impression!