A good way to get other sites to link to yours is to provide information that is good enough to link to ("link attractors"). So if you have for example a car valeting business you might include a page of tips about cleaning your car. You can also use your own links page to hold links for example to suppliers information, product data sheets, anything you and your customers would find useful.
Here you will find a page providing links you may find useful in promoting your business.
skillbank.co.uk has its "link attractors" on separate sections of this website, accessed here.