From the Admin go to users/user roles and define a student and a College user.  Then modify the Profile Questions related to each of them and possibly their permissions.

Hope it helps.

Thanks for your reply. Profile questions is not exactly what I'm looking for.

I'm looking for changing certain features or turning features on or off, which, sadly is not covered in role permission management page. 

Also, since the "Free" role is default for all, the permissions are not working for me either.

I wish to know if there's any way I can get this done? may be a plugin?

Thanks.

>>Lets say for example, we need to create a student profile and a college profile.

Students can make friends but can only follow a college. Also, it's important to have just one college for any student. Students cant add college as friend, neither can college do that to a student.

This kind of feature, indeed, requires some custom code modification ( for ex. Oxwall doesn't have built in feature which would restrict students from adding colleges to friends).

With regards o "Free" role being default one. You can always change which role is a default one using drag&drop.

Thanks, I didnt know we could change the default role. It was helpful.