Intro
If search engines determine that your website is popular, then they will list it as relevant to a search, the more popular - the more relevant. The more relevant, the higher you will be listed in search results. But how easy is to be popular?
Design to become popular
The search engines calculate that if other websites containing subject matter in common with your website, have actually linked to your website, then yours is a popular site for that subject. The more links from websites with the same key words as you, the more popular your site is deemed. Plan to get those prized links.
Key words
What search words do you want people to find you by? These should include your subject, your products, or services, or information, but could also include location, country, state, town. If you want to be relevant to a search for 'toys Australia' - you need links from toys websites and from Australian websites, but not from competing toys sites in Australia.
For your subject, find websites in other parts of the world using your key words, but who don't directly compete with you.
For your location, there are small business groups, local chambers of commerce, portals and other websites in your location looking for links for the same reason as you.
Non-reciprocal links
There will be sites that will link to you without requiring a reciprocal link back from you. These include some location sites mentioned above. However, remember that a link from you also helps them appear popular, which in turn helps you. You want links from popular websites.
Reciprocal links
Websites in other locations with web pages rich in your key words are ideal links to you, and your website would be an ideal link to them. If you are selling pizzas in Sydney a link from Joe's Pizzas New York will help with the key word 'pizzas'.
Websites in your own location are of value for the location words. e.g. If you want to be found in a search for Sydney websites, links from other Sydney sites can help. If you are selling toys in Sydney, a link from Joe's Pizzas New York is unlikely to help.
Asking for a link
When emailing another website, avoid making a request that looks like a form letter. Send a personal email offering to swap links, listing particular key words that your websites have in common.
Check where your link will be on the other site. Check that their home page links directly to their links page. Avoid websites where their link to you won't be direct. Run your mouse over their links to other sites. If a link looks like an internal database reference, e.g. resources.asp?ID=1234, it is too indirect to be counted by search engines. The link should be http://www.yourwebsite.com.
Many websites may ask you for reciprocal links. Evaluate these against the above criteria.
Placing a link
Links to other websites can be on any page of your website, but it's useful to have some text on that page containing your key words. To persuade other websites to swap links, that page should be linked also directly from your home page. Many websites have a page especially for reciprocal links, or 'resources' as many now call it. Your web designer can help.
Many websites will email you the HTML code for a link to them. You can copy and paste it on to your page, or your web designer can.
Supplying link details
You need to email the other website with (1) URL in the format http://www.yoursite.com, (2) title including key words, and (3) brief description including key words.
Be popular
The more relevant links you can get the more popular you will be. Your website will be just what the search engines are looking for.