Hi Sourabh, before getting into iit if you are focusing on the coding skills, I would suggest start with C, then ,C++, python etc. It depends what sort of branch you are aiming for. This is beneficial whether you are a cse,IT or and ECE student. In order to command English, start with reading small articles from magazines and try out books and novels. Enusre whenever you encounter new word, you find its meaning and learn it too. There are Courses available on udemy, Coursera in order to develop new skills.

All the best.