I want to hire people on a contract basis to deliver flyers door-to-door. I want to protect myself and my company from any liability should they cause any damage or are injured.
What items do I need to make sure to cover in a waiver?
You may want to research a day labor company - I know Labor Finders is one- or a temp agency. This way, the workers are actually employees of the labor company. You pay the day labor company for the workers and the day labor company pays the workers their wages. I don't know if this will protect you but since they are not your direct employees may provide some type of protection. Of course, the down side - you may not have much control over who they send out.
You can't "waive" your liability. You can't "opt out" of the law.
If you want your company to be protected, you need to carry general liability including advertising liability, AND, if your "contract people" don't carry their own workers compensation, YOU need to carry it. When you subcontract work out, to uninsured subcontractors, YOU are on the hook for the workers comp benefits - even if you don't carry the insurance.