A lot of free time

I know how you feel bro because I'm also a student soon after finals so I have too much free time on my hands. In any case what I would recommend is just start doing what you like (for me it's reading books, watching series/films, playing video games - though you have to be careful with the last one because imo it's not really productive). That would be pretty much to take most of your time. Other things worth doing is trying to find a new hobby - it may be hard and you would probably lack motivation for many things but it's good to at least make an attempt at something for a few days to see how you feel about it. If you are an outdoor type (and you want to avoid PMO as much as you can) then go for walks, use your bike, hit the gym - I haven't really commited to these lately but I know from previous experience that they help with controlling your urges. If, however, you prefer to stay at home, then it may be more tricky but you can still maybe learn to do some useful things around your house. And one last thing - avoid boredom, tiredness, and stress - these three (actually having so much free time probably only the first one) are, in my humble opinion, your biggest enemies when it comes to giving in to the urge. The best way to avoid them is to head straight outdoors, after all I do not believe that there are many who would stoop to masturbation in public.
Peace!

 

There's literally a ton of things you can do. The best option I reckon is to check websites online to pinpoint what interests you. Here's some to take a look. Maybe, you'll find something.
http://freeintenyears.com/frugal-tips/100-cheap-hobbies/
http://nextluxury.com/mens-lifestyle-advice/top-75-best-manly-hobbies-for-men/
http://9creativelives.com/2012/12/150-activitieshobbies-to-start-or-revist-when-youre-bored/

 

Just read. Read anything you can.

 

Focus on your school. DOn't distract yourself. Improvement can wait once you master your grades.

 

Ok, then I suggest you learn a new language, learn a music instrument and pick up a sport. After you've done that, you can play a video game or watch a tv show at the end of the day.

 

I second Genji^ It's a good idea to use this reward technique (or whatever you call it). First you do something creative, then you can slack.

 

Great. If you still have some time left, try volunteering somewhere. Nothing builds character faster.

 

@ARezE 1984 by George Orwell is a book I think everybody should read. It has some great commentary about society. Also his other book Animal Farm is a great metaphor for the Soviet Union. The "Gone" series is also great. Every one older than 15 disappears and a dome forms around this town. Some kids get powers and everybody tried to survive. It's pretty good.