To all the freshers out there trying for a department change I have only 3 pieces of advice 1) Whatever happens don't lose hope. Irrespective of how you score in your midsems, you have to realise that you can easily make up for it during your endsem. This I say from personal experience. Learn from your mistakes and things will work out.
2) Don't be obsessive about marks. If you make marks your goal rather than learning something for the long run, there is a good chance the efforts you put in may nor bear fruit. Study with the intention of learning and try to enjoy what you are doing. You will see the results yourself.
3) Manage your time well and study regularly, even 1-2 hours a day is enough on regular working days. Follow this and you will have a lot of time to enjoy your first year too. Best of luck to everyone :D