Hey,
Yes, you can do graduation in arts and commerce at Jamia but you need to give the entrance exam .

Actually the entrance exam is combined  for BBA ,B.A.(h) Economics and B.com. The question pattern is simple- some basic maths( Quantitative aptitude),Reasoning, GK and English.

For preparation of Quants and Reasoning, nothing can substitute practice. Since its basic quant and reasoning, so a little practice would help you to get ahead of your competitors. For GK, update yourself with current affairs. You can also prepare from Arihant GK book. Read that regularly. Lucent (GS Book) would do too, but the question paper level isnt that difficult. I would suggest make more use of internet for online GK tests and quizzes. You never know the paper setter might be using the same link! plus it includes current affairs. Do not forget to revise the GK stuff before exam.

Coming to the English part, I have only one answer-just read as much as you can. Try to work out the meaning of unfamiliar words while reading by their usage and root words. Vocabulary can be improved by reading only. If you are very dedicated, can devote time and wanna improve your vocab and English forever read Word Power Made Easy by Norman Lewis, believe me it will exponentially enhance your vocabulary.
Thats it.
Study hard and keep yourself calm during exam, you will crack it easily. Best wishes.