Hey,

For management principles you many take in consideration T. N. Chabbra as it is been followed in the university of Delhi and is considered apparently good for your semesters exams.
For Income tax go for Dr. Vinod K. Singhania it would quit better for you. The language is comparatively easier and have good number of examples for practice.
For Ecommerce you may go for ecommerce book sushma arora.
Hope this helps.