Maintenance Contracts

Sorry for having to put this here, but I didn’t get any responses from the IT Consultant forum. I’m trying to figure out how to present a maintenance contract to some new clients but I don’t know what I should be covering and how much I should be charging. Normally our hourly charge is between $85-95 an hour, so how would that get rolled into a maintenance contract/agreement? Do I cover service only up to a certain amount of time? Do I just show up X amount of hours per month? Do I cover certain tasks laid out in the contract/agreement? How do I do this and still make a profit??? Thanks.