1. equal opportunity in prize selection,
2. prize selection criteria to be disclosed,
3. the maximum amount of prize that can be offered,
4. the sweepstakes can be withdrawn without any notice,
5. disclaimer need to be mentioned on the website,
6. no proprietary rights to claim the gifts,
7. do not offer any gift that has health hazard,
8. mention the gift offered is for which class or category of users, etc.
Similar to above, many terms and conditions may be drafted on the website.
thanks.