If you were to rank all the positive attributes a business must have in order to succeed, which would be No. 1 on your list?

A quality product or service? Highly competent employees? Top-notch customer service?

All are critically important, of course, and you can easily name several more. For me, though, one is most important.

It's trust.

Unless potential customers or clients trust you and your brand, you'll have no chance to gain their business, let alone their loyalty.

But trust must be earned and cultivated. Here are four ways you can do that.

Stand on your history

Whether you've been in business for decades or just starting out, you have a history. So use it to help people develop trust in you and your brand. If your company has a long history, tout it--its successes, the quality and reputation of its products or services, the testimonials of happy customers. My firm, for example, has been in business for 30 years, so we highlight that fact prominently, showing on our website all the awards we've won and even providing a timeline of key milestones. You can do the same on your website and via your marketing channels.

You can highlight your history even if you're new. Talk about your experience, your passion for starting your business and your commitment to doing for your customers what they haven't been able to get from other, older, more entrenched companies. People love to support start-ups --evidenced by the popularity of new restaurants. Don't let your newness be a liability; convert it to a marketing tool.

Subtlety in marketing

How do you feel about hard-sell advertisers who generate annoying, repetitious messages? Pushing too hard can engender distrust: If you have the greatest product or service, you shouldn't have to pummel people with claims to that effect. So try a more subtle, respectful approach with your messaging. Advertising, after all, is the first impression potential customers or clients will have of you; any marketing, advertising or PR campaign must reflect the personality you want people to have of you and your company.

Speak with authority

Look for opportunities--or invent them--to offer your opinion. Be definitive and, whenever you can, be controversial or unconventional. Those two words were ascribed to me years ago by the media in response to statements I made on my radio show. The result was third-party endorsement and confirmation of my credibility. You can do that too. Just make sure that whatever you say is accurate and complete. In other words, tell the truth. It's the basis of being trustworthy.

Prove you're accountable

Trust is gained over time, so always deliver what you promise. Many firms try to succeed by seeking ways to deliver more than they promised, but let's not be so aspirational at first. Start out by just honoring your promises. If you have a money-back guarantee, honor it. If you promise same-day delivery, fulfill it. If you promise to fix a problem, fix it. You might be tempted to focus first on exceeding expectations, but that doesn't build trust; that builds loyalty--which is entirely different. Trust is earned by doing what you say you'll do, not by doing something different.

Eventually, your history of fulfilling promises will become known--because consumers will tell others, often via online reviews. Third-party endorsements are vital, because trust is infectious: If my friend trusts you and I trust my friend, I will therefore trust you. So use testimonials and third-party endorsements as often as you can. (Securities regulations don't allow financial advisors like my firm to publicize the testimonials we receive from our clients, but your business might not have such restrictions.)

These four trust-building ideas can help your audience learn to trust you. As I said at the outset, trustworthiness isn't the only attribute a successful business needs, but it's definitely the most important.

Trust me on that.