The price to be paid. This part should be very clear, what you want to know is if the contractor is being paid per hour or per job. But if the wages are per hour you want the price to have a cap. What this means is after a certain number of hours of labor, they no longer get paid if work is not complete. This will keep hourly employees from dilly dallying.
 Who is responsible for paying for what? Basically as part of your contract you want to specify whether or not the overall price paid includes materials or if the contract is just for labor. You also want to determine who is responsible for purchasing the materials. And what happens if the materials or something else gets broken who is responsible for paying for getting it fixed. This all needs to be specified.
 You should also be given a specification on how long they think the job will actually take. It is important for the sub to give you a time line; they should tell you how long the job will take them. You then need to include this in the contract. You need to include a date and time they will start. What time each day they are expected to be on site, and when the job must be finished by in order for them to get paid.
 You also want to include where the work will be preformed. You will want to specify where it is that the sub contractor will do work and what work is to be done. You should actually include the full address to the work site in the contract.
 If the work takes longer, or causes delays in other people's jobs you are going to want to know who is going to be responsible for these costs. What is usually best is to attach a financial penalty to the contract for each day that they are late. If they say things will be done in 5 days, and it takes 8, you should be able to take $50 a day off the price you originally agreed on. This will motivate them to get things done on time, and protect you if they don't.
 You will also want to include in your legal contract any exceptions to any of the work that is to be done. For example if an earthquake happens and breaks all windows, they do not have to pay for them, or if a hurricane comes through and rips the roof off, etc.
 Who is responsible for direct costs? If they are traveling to your site everyday, are you responsible for their travel costs? What about their lunch? Be specific about what is paid for by you and what is going to be their responsibility.
 Have a clause about who will order, pick up, and pay for all of the materials. This is important because if you are supposed to, and you don't and that is why they can't finish on time that is your problem. But if they are supposed to and don't, then the excuse of not having the materials does not fly.
 What things are included in price/bid? Does their bid price include just labor? Does it include materials? Does it include some materials but not others? What about clean up?
 You want to have a clause about safety that requires them to wear proper attire, drink water to stay hydrated if working in sun, wear hard hats, etc. this clause protects you should accident happen because of their neglect. It is also important to include safety of materials, meaning if things get stolen, they are responsible to replace them. (this deters them from stealing materials, and reminds them to lock up and secure the site).