As part of our 'Real Customers, Real Service' series we've been investigating what makes an exceptional customer experience. What should companies do to keep their customers coming back for more?

The poet Maya Angelou wrote: 'while people may forget what you said and did, they always remember how you made them feel'. That's very true when it comes to customer service.

Outstanding service can leave you feeling positive, valued and likely to want to repeat the experience. Terrible customer service can leave you feeling stressed, frustrated, angry and, in many cases, never wanting that experience again.

Top big brands rated for customer service

When we asked thousands of Brits about the brands they rated most highly for customer service, Lush, Lakeland, First Direct and John Lewis topped our league table. Cosmetics firm Lush is the clear winner in our 2013 survey of 100 big-name brands, being the only brand to achieve an 'excellent' five-star rating for having knowledge and helpful staff, and for making customers feel valued.

Ryanair, TalkTalk and Npower need to pull up their socks, however: these brands limp into the bottom places of our survey. If you're a Which? member, you'll find the full results of our 2013 customer service survey in the October 2013 issue of Which? magazine, which can also be found online.

Top five points for good customer service

With those winners and losers ringing in your ears, here's our advice for companies who want to inspire loyalty in their customers:

1. Exceptional customer service more than pays for itself. Happy customers are loyal customers; loyal customers are profitable customers.

2. Value your customers and they'll value you. Treat each person as an individual. Understand what your customers want and don't waste their time by keeping them waiting and not being able to sort things out first time.

3. Invest in your staff. Your customers are likely to judge your brand by its staff, so investing in recruitment and training will pay dividends in the long term.

4. A complaint is a gift. Senior managers need to listen to feedback from staff and customers and act on it. If things have gone wrong, see that as an opportunity for improvement. Seize the chance to recover the situation, and retain rather than lose customers.

5. Don't rest on your laurels. Respond to changing customer demand. None of the companies that excel in our survey have done so by failing to innovate or improve. Complacency hasn't got them there, nor will it keep them there.

What do you think of our advice for companies? And what do you think makes companies stand out for good (or bad!) customer service?