How can I make sure my business contracts are airtight?
You need an attorney, that’s always the best solution in situations like this. Specifically, you should go to this website or a similar one and ask for advice on having all of your current contracts — or all the most important contracts — reviewed by an attorney.
A seasoned business and acquisition attorney will easily be able to spot any glaring issues with your current contracts. Whether it be spots where the language isn’t clear enough, missing or inaccurate information, provisions that can’t be enforced, provisions that aren’t legal, contracts that are too one-sided, etc.
Should your attorney find any issues with the contract, they can also advise on how to proceed. Whether it be by negotiating a new contract, amending the existing one, changing business partners, or some other measure meant to reduce liability. It is often obvious when a contract was designed in bad faith to begin with, after all, so a business partner that asked you to sign something unsavory is someone you might want to cut ties with.