What should I be looking for when we draw up papers or what things should I be thinking about that I want out of the contract?

When you are investing in a business, you need to consider whether you can bringing added customers or markets to the business or are you relying on the seller to maintain the business and its current customer base. If you have customers or a market that will add to the business, then you should focus more on the infrastruacture (or assets of the business), like whether the assets are owned outright and whether the employees are going to stay. In this scenario, you tend to care less about the company's financials or the customer base because you have the customers, and only you need to make sure the infrastructure is secure. If, on the other hand, you are heavily relying on the current business, then you have to look at everything, including infrastructure, the financials, and making sure the customer base has solid long term relationships. Also, you have to secure certain voting rights as a shareholder or partner in the business - like sell of the company, dissolution, or new partners. You need to have an agreement on to handle things like divorce, disability, and death. Lastly, if you are going to work in the business you might also consider an employment agreement.