Drafting a contract that accomplishes all your business goals while addressing all possible complications is not easy. The language in a contract should be clear and the parties should make sure they agree on every point.
The most important point in drafting a contract is simply to get it in writing. It is possible to form a legally binding contract without putting pen to paper, but if any problem arises later on it is a lot better to have a written document to which you can refer.
The language you use in your contract must be precise, but especially in the context of small business, it should not be difficult to understand. A contract is meant to express the agreement of two parties; if the parties can't even agree on what the terms in the document mean, then the contract is not doing its job.
Your contract should include details of how payment is to be made. This is one of the aspects of contracts that is most likely to lead to litigation later on, and so you want to make sure that all parties are clear on when and how payments are due, and how payments will be calculated.
It's important for all parties to include language that provides a way to terminate the contract. You want terms that bind the parties to perform their parts of the contract, but also provide a way to end the agreement should it become necessary. Some contracts may include a mutual termination clause, or provide a way for either party to terminate the agreement if the other fails to fulfill the agreed-upon obligations.
These are just some of the things you should think about when preparing a contract. An experienced business lawyer can help you draft a contract that fulfills your business needs and will stand up to legal scrutiny, should a dispute later arise.