Create Desi Matrimony website like [url removed, login to view] or Jeevansathi.com. Must have all the features which those websites have.
Basic and Must Features include:
Must be very attractive UI Design better than Shaadi/Jeevansathi with intuitive user interface
Online P2P chat with status changing option along with history shown in separate tabs.
User Profile, Dashboard, Preferences, Privacy Settings, General Settings, Managing Photos etc.
Complete Message Inbox System that includes members accepted, invited, Pending
Payment integration for credit cards, paypal etc with one time, monthly, yearly, weekly automatic payment cycles
User levels, e.g. Basic, Premium, Gold and complete admin system to restrict each level for particular feature.
User Profiling for Customer support for providing ID etc.
Integration with social media e.g. like facebook, twitter etc.
Basic and Advance Searching on each criteria selection.
Intelligence integrated for partner preferences and show matching and recommended profiles
Complete Notification and feed system with email, SMS with unsubscribe option. All kind of notifications including all events like signup, new request, accepted, photo added, photo approval/denied and others check on shaadi.com
Also verification of person for each system through email and phone.
First time login shows proper interactive tutorial how to use website.
Complete Admin system for Customer support that controls each aspect of profiles
Customer Support Help/Chat
There may be some other features which i am missing available on those website. Please do some research as well to figure that out.