Mostly all of the firms do also have off-campus recruitment drives/lateral hiring going on throughout the year besides the on-campus recruitment drives. For the same, keep an eye on the LinkedIn job portal, their career pages and LinkedIn posts by the employees at these firms. One thing that could help here is tapping people for referrals!

Thanku for the info..but other then referrals,what all skills to work on.. so that during the interview it would help me to get in as I don't have any experience w.r.t buisness fields.