Links are a very crucial part of any SEO campaign. Not only that, but building links will also help drive traffic to your site from others too. There are two types of links really, they are as follows:
Internal links are links that are from one page of your website to another page. This will help people navigate around your website until they find what they are looking for. Internal linking is also a strong factor of natural and ethical search engine optimisation. Internal links help the search engine site crawlers to navigate around your website and find new content that they have to update Google with. Correctly building internal links on your website will ensure that your site is promoted ethically.
External links a links that are pointing to your website from other website or web pages that are not connected to your site in any other way. There are a couple of uses for these links. The first use is to let people know that your website exists, people can click on these links that are pointing to your website to find your products and services that you have to offer them. The other reason, and probably one of the most important factors of search engine optimisation is link building so that search engines can see how many other sites are pointing to your website via these external links. It is important not only to ensure that the anchor text of the link is your keyword, but to also ensure that the links that are pointing to your website are from other themed websites. This means that the website pointing to yours should be of the same content, or relevance.
The more links you have from other trusted websites that are themed, the bestter as far as the search engines are concerned. Be careful not to build links too fast to your website, or you can be penalised by Google for over optimising your website.