Hi Satish,
It would be really helpful if you can specify what type of business is your company into and what kind of colleges are you targetting.
However, for me the purpose of campus interview is to sell your company to the prospective candidates and also to set the expectations, so that you can select the right candidates as per your requirement.
So please prepare a presentation to be given to all the candidates, which covers all the above mentioned points, i.e. about your company, what can the candidates expect from your company, process of selection you are going to follow.
THen see if the entire selection process is going to be followed at the campus itself. If yes, please chcek if you have all the arrangements ready.
Please see if you have the right mix and number of interviewers available. When i say interviewers, i am stressing more on the technical interviewers and then the HR persons.
Check for the infrastructure and prepare contingency measure.
For Eg, if you have planned a computer based test and if the power goes off due to some reason, you must be able to carry on the process through the paper mode.
These are my suggestions. All the best for your first recruitment drive and hope you enjoy it.