I guess this can be for any subject, but I mention science specifically a few times (though you can easily exchange it for whatever subject)

Sherlock:

He takes some liberty with it...and by some liberty, I mean he does something completely different because he thinks the actual project you have to do is boring, meaning no one really wants to work with him because you'll have to do everything yourself.
He's the perfect person to work with if you wanted to work by yourself anyway—once you get done with doing the actual project, you ask him what he's working on, and the two of you likely become friends through this because you're the only on who has ever shown genuine interest. 

John:

It depends if the science. He's really good at biology, astronomy, and anatomy and physiology. Chemistry, not too much, you'll get a B at most if you're following his lead. In physics he's decent.
The two of you talk quite a bit (mostly sarcastic quips and comments, and jokes). 

Mycroft:

He'll take the lead because he knows exactly how to succeed in the class. He'll only take a step back if he has grown fond of you for some reason (though no one will ever really know this reason, including him). Even then, him "taking a step back" is letting you work on it for one day, before finishing it himself the next. 
Even if he does have this "fondness" towards you, he doesn't know how to express it, meaning you'd have to put in most of the work. 

Moriarty:

I feel like he would end up doing some thing extremely outlandish—the teacher would either love him or hate him, and also either hates or loves you. This does have an impact on your grade, meaning you'll either get the highest score, or the lowest score. He definitely bends the rules, and when the teacher says to look at the rules carefully, the statement is directed at him. 

Molly:

She makes sure everything gets done properly. She's quiet, smart, and makes pretty good grades in school. The two of you end up working on the project in the library and you get a good grade.