This is where a sample template can also help. You can search for a commercial lease agreement sample for your state to help you get a good idea of what your lease agreement should look like, of what is required by law and of what you should add to your own. Make sure to find a few of good ideas to give you as many ideas as possible about how to put together this form.
Since the possibility of disputes is always present your agreement must include a place to cover how any disputes will be handled. This way everyone has already agreed to how these disputes are to be taken care of and cannot argue the point and cause further problems for the rest of the members of the venture. This may end up being the most important area of your agreement and should be filled out very carefully to avoid any possibility of a legal challenge.