Here are a few:

Food: If you can’t manage the home-sickness related to food, it will be a bit difficult - if you are planning to stay in a hostel. If you are planning to eat out, I don’ think you will get a better diversity in entire south India than in Bangalore. Bangalore has got some best restaurants of cuisines from all over the country.

Security deposit on rent: If you are renting a house you might have to shell close to 5–10 months rent as a refundable deposit, depending on your negotiation abilities.

change in temperature 

language problem

Feel free to ask me in the comment box if you are having any further doubts

hope you find it helpful 

Good Luck!