Here's a piece of advice that many founders give and that seems to produce results.
It is for all employees of the company to regularly spend time on customer support. Whether it's by phone, chat or email. Lemkin talks about a minimum of two hours per shift, but this is obviously to be adapted according to the context.
I have personally spent a lot of time doing customer support in my companies, and it was quite natural for people who were close to the product design to do it as well, such as Product Managers. But I have never experienced systematically extending this to all employees. I have no trouble imagining the benefits, though.
The customer's voice comes unfiltered to the teams. Software engineers can hear their problems directly and sales people gain insights that help them adopt their point of view.
The maturity of the customer support tools used by all startups makes this access particularly easy to implement. However, this requires good planning with the support team already in place, as they will have an extra workload to ensure the second level for these beginners.
An approach that is worth testing in your organization to measure its benefits.
A personal note of caution: I would recommend doing this only once the product has reached a certain level of maturity, so that the discovery of problems is not counter-productive with the sales teams.
Love it. I implemented it, over some complaints. And it worked magic. It worked magic with engineers, who really heard the complaints. They learned. It worked its magic with the sales team (believe it or not). While they used Adobe Sign / EchoSign ten times a day, they didn’t really see it from the customer side. Even my most experienced reps loved the experience — and sales reps don’t usually want to waste time on anything that doesn’t make them money.