6. Never Let Two Opposing Attorneys Be Alone Together

"Never let lawyers by themselves or take control of your process -- be there," he said.

This doesn't mean that opposing attorneys aren't allowed to talk once and a while over email, but Chesonis' rule of thumb is to first sit down with them and both businesses to get a lot of work done. By the second in-person meeting, you'll be almost done and preparing to verify final drafts, he explained.

"Don’t let attorneys (be) by themselves -- even if you have a good in-house counsel. Make sure you are with business leaders from both sides because things get twisted and then delayed, and cost you more money," Chesonis said. "That took me 25 years to figure out."