In-house legal departments face constant pressure to control costs, and many are opting to use fewer outside firms when they do outsource work, making it “very competitive” for firms vying for new clients.

The biggest opportunity for a law firm to obtain new clients often occurs when leadership of the in-house legal department changes.

"Someone should be tasked with identifying when a GC is retiring or replaced, or the No. 2, who is often the one who assigns a lot of work," said Tom Sager, former DuPont general counsel and current Ballard Spahr partner, suggesting firms should have more formal programs in place to identify those opportunities.

Firms could have their marketing teams implement a "disciplined process" by which any time there is word of a leadership change, the firm has a way of canvassing all of the attorneys in a proactive way to see if any of them have relationships with the new general counsel, Sager said.

"That's where I think a lot of firms miss the boat," he said.