1. Make it convenient
Convenience rules our world. It's the one thing that is more important than "cost". If its easier than something similar, they will use it. So, use a simple domain your audience can remember, provide the address on your email, cards, brochures etc. Provide the address of any online tools in literature or maybe supply an App they can download that specifically sources or delivers information for them. Anything you can do to help your audience easily find you, see you or use your service is seen as being convenient.
2. Provide value
Provide service or information that helps customers speed up what they need to do. You must do this over and above what others provide as a normal service and/or over and above a service you may charge for. Giving customers something that truely helps them for no extra charge gains trust. Self help tools are good but they need to be easy to use, work all the time and stay current.
3. Make it easy
When you're doing 1. and 2. well, don't ruin it by asking customers to login or something equally annoying. Equally, make your site easy to use by doing pre-live user testing. This does not need to be expensive or long winded - ask your neighbour, parents or kids to carry out predefined tasks that you have determined your customers might do on your website. Make it easier than your competitors, help customers do what they want to do quickly and they will talk about you as a market leader. Make your website a pleasurable self-help experience.
4. Don't copy competitors
Remember what your teacher used to tell you about copying someone else in a test? The person you choose to copy could be wrong. Just because most other competitors in your market do similar things online, it does not mean they are right. Unlike Offline, Online is still a mystery to many companies so they tend to copy principles used elsewhere. These date fast and were often never right in the first experience. In my experience, it is better to trial something yourself, measure it, then tweak the site. Better to learn trying than be ignorant copying.
5. Do the basics - do not experiment
If you're a manager charged with heading a website project, any success you might achieve online will be largely to do with your willingness to do or help with what it is your customers need to do. Business websites are 99% destinational - they are tools that support and supplement your business offering offline. Websites are not experimental projects where you can afford to waste money on designs to please your boss or yourself. Find the truth, ask your audience and follow these principles. And remember, good things take time, make small tweaks to your site every few weeks and measure the results and re-tweak. This is how those good sites became so nice to use.