Well done. You did well taking the first step: admitting to the problem.

Focusing on studies is a big issue for any student. One way to do it is to go cold turkey. Uninstall all your games, and give them to a trusted friend in case you're tempted to reinstall them. You could also unplug the cords that connect your games and give them to your trusted friend. Tell them not to give them back to you until you're finished studying.

Practically however, you might find it more useful to develop skills that will help you control your focus. To help you focus, you will probably need to set some goals. For example, decide if you want to do really well in your studies, be an average student, or just pass. Once you have decided this, you will have to work towards it for your goal to become reality.

Real focus is developed slowly and through a daily schedule. Say you decided you want to do really well in your studies. To do this, you may have to study 10 hours a day. It sounds a lot, doesn't it? Well, not really if you think about it in say 2-hour chunks. Most people find it more helpful to break a big chunk of time into smaller chunks. If you're like most people, you will find it a lot more do-able to study in 5 chunks of 2 hours instead of one chunk of 10 hours, and to spread each 2-hour chunk across your day.

Get an alarm clock, or use your phone. Set your alarm for 1.5 hours and then a reminder for the next 30 minutes as a wake up call. Do this for every chunk of studying time. This should help you feel a sense of achievement each time.

If you follow this and still find it difficult to focus on your studies to start with, try not to be too hard on yourself. Just keep at it. You should find that you will gradually become better at controlling your focus and become more resistant to the distraction of your games... and one day you will be controlling your focus without even realising you're doing it!

Good luck!