If I may offer some advice when it comes to contracts.
It is vital that your contracts are specific to your business, your policies and terms and conditions. You must know your contracts in and out so that you know what your asking of your clients.
We for example have invested a lot of time and money to create an in depth contract which covers all aspects we require.
I am guessing your just starting out in commercial cleaning contracts so a pretty basic statement of terms and conditions would probably be best.
Write down the main points you want your customer to adhere to, for example, they agree to the specification and price you have issued. The payment terms; method and time frame. Any penalty for late payment. Any time frames or cancellation terms of the agreement. Clearly state who supplies the products and equipment. A good point to include is also one for any statutory increases for example minimum wage increase - this clause will allow you to pass these increases onto the customer.
I hope this helps, you will be far better writing your own contracts so that you fully understand them.