>>What is the best Precausion (Disaster Recover plan) should i have to followup?

Keep good backup of all dbs.

>>What is the method should i have to taken inorder to smooth migration bt the server?

backup/restore user dbs, can sql logins and jobs with ssis.

>>What is the tools should i have use either SSIS or normal Backup and restore?

ssms to backup/restore, bids for ssis.