You ought to consult an Ohio Real Estate Attorney . . . . or if you don't want to spend the money for that, review the Forms and concepts available through
www.LegalZoom.com !
Here's a Primer:
Negotiating Commercial Leases For price per sq ft, evaluate what other Lessors (LandLords) in your area are asking (and getting) in your area. What are they requiring for a Security Deposit . . . . and what alterations will the Lessees (Tenants) require you to make to the property to make it suitable for their purposes ?
For Terms and Conditions, the Charter School probably has an Attorney on its Board and already has lots of special Conditions that they'll be expecting you to accept. These will be for their benefit, and you'll want your own Counsel to review and propose what's best for you . . . . regardless of whether you're dealing with a not-for-profit.