Backlinks remain an important component among the more-than-100 items Google’s search-engine algorithm considers to calculate your website’s position on a search engine results page (SERP). That's why they're important. But achieving a strong backlink portfolio using only white-hat (ethical) SEO tactics can be challenging.

Related: The Savvy SEO's Guide to Backlink Analysis

Still, it is possible to get high-quality backlinks. The following five tips will show you how to improve your backlink portfolio over time, and move your site’s position up in the bargain.

'High-quality' backlinks defined

First off, what does "high quality" mean? Google weighs several factors to assess the validity and quality of backlinks.

  • Domain age: There’s not much difference between a domain that's one year old and one that’s six months old, according to Matt Cutts, Google’s guru of all things SEO. However, older sites with consistent ownership prove that the site is trustworthy to the Google gods, and these factors give links stronger weight.
  • Link authority: Domain age, keyword relevance and other items all go into link authority. Link authority also adds to how much weight Google gives your backlink. To check your link authority, use Ahrefs: a great tool to check your current backlink profile and check link authority from other sites.
  • Natural link patterns: Search engines have gotten wise to the so-called black-hat SEO techniques popular in the pre-Panda and Penguin days when people set up link farms for the sole purpose of pushing backlinks into websites. The poor-quality sites often charged for the pleasure of spreading spam. These days, however, Google and other search engines are sophisticated enough to look for natural linking patterns into your site as opposed to dozens of links coming from low-quality parked domains. Natural patterns reflect a wide range of sites, with some being high authority and some low, and from keywords related to your website. If your website sells aquarium supplies and links are coming in from tropical and saltwater fish hobbyist blogs, that seems logical. If the links are coming from sites completely unrelated to fish and aquariums, red flags will be raised.
  • Exact-match anchor text: Exact-match anchor text remains an important component of high-quality backlinks. Anchor text related to your topic, rather than anchor text like “click here,” adds weight and validity to backlinks.

Related: 5 Sources of High-Quality Links for Local SEO

5 tips for high-quality backlinks

Obtaining high-quality links like those described above may seem a tall order. But smart marketers know that there are methods to obtaining high-quality backlinks. These methods take time, and then even more time to boost your site’s position in the SERPs. That won’t happen overnight. But these methods are both proven and ethical for increasing your backlink profile as part of an overall SEO strategy.

Tip 1: Review your current backlink profile. Take time to review your domain’s current backlink profile. The previously mentioned Ahrefs is an industry standard tool that provides a wealth of information, but there are others to help you examine your site’s link profile and domain authority. They include Majestic, Moz, Small SEO Tools and more.

Start a file on your computer, or a spreadsheet, to record your site’s current link profile. You’ll need this to track progress over time and your work on your backlinks profile.

Record your site’s current backlink profile in your folder or spreadsheet. How many links do you have? What sites are they from? Visit some of the sites to view their quality. Check their rank and authority. What content is attracting links, and can you capitalize on those keywords?

Tip 2: Create a list of your top posts and keywords. You have to give websites a reason to link into your posts. Relevant, authoritative, engaging and unique content forms the backdrop of all inbound linking activities. Go through your current website and develop a list of your most-read content and keyword phrases that bring in the highest traffic levels. You’ll use these as a springboard for your backlink development efforts.

Tip 3: Add long-form content to your site. Long-form content, roughly defined as content over 1,000 words, attracts backlinks. In one study, the average Google first page search result contained 1,889 words. Look for good content on your own site now that can be expanded into online guides or longer pieces. Add images to your content, too. Another study found that pages which rank well have at least one image.

Tip 4: Generate a list of websites that you’d like to link into your site to start a guest posting effort. Guest posts enable you to add natural backlinks to your website from a wide range of sites. You pitch an original topic to a webmaster, and if he likes it, you submit your post. In exchange for the content, the webmaster links to your site. It takes time to develop content for other sites, so pace yourself or hire a freelance writer to create guest posts for you. Don’t repurpose existing content or use duplicate content; that can hurt both your SEO efforts and the site you’re pitching.

Use your folder and spreadsheet to develop a list of websites that you’d ideally like to link into your site. Find the contact information for the webmaster, and add that to your spreadsheet.

Tip 5: Pitch your best content to websites. Another strategy to obtain backlinks is to email the webmasters on your target list with a pitch to link into your content. If the content is good enough or relevant enough to their sites' target audience, they may consider your request. Provide them with anchor keyword phrases you’d like to have linking into your site, and be patient. They may take weeks to respond.

Related: Here's What Really Matters for SEO in 2016

Obtaining high-quality backlinks in 2016 is a task that takes time and effort, but it’s still possible to improve your backlinks profile. Backlinks remain an important component of how the search engines calculate your site’s position on SERPS. The more you can improve your backlink profile, the better.