Search Term Selection: Use tools like Ahrefs, Moz, and Google Keyword Tool to find terms applicable to your business that have high search volume with low competition. These (typically long-tail) terms are going to be the easiest for you to go after early on.
Content Quality: Write highly compelling content for each search term you're targeting. Try to limit the number of terms you target at first (don't go after 100s or 1000s of keywords on day 1), and instead focus on creating highly valuable content for a handful of them, and then growing that content breadth organically as your domain rank goes up.
Content Structure: Ensure all of your Unstack content contains a top-level H1 that matches your Title tag, a good Meta Description that's both compelling and applicable to your search term, and a good mix of H2s, H3s, paragraph text, and alt tags on your images that correspond to the search term each individual page is targeting while being different enough that it doesn't look like keyword stuffing to Google, When deciding on content length and keyword density, there are mixed opinions. From my observation, more content is always better (a la Nerd Wallet), and keyword density shouldn't be something you focus on. Just write naturally on a topic, and you should be golden.
Interlinking Strategy: Ensure all of your pages and blog articles interlink in a way that makes sense and guides readers and search engine spiders to other related content. Using links in content in an article is a great way to allow readers and search engines to follow a link to get more info from another article or page on that topic. Using Unstack's smart-links, you can be sure that these will never become dead links, and will follow the linked page even if you change the URL (side note: we'll also automatically 301 the original page URL to the new URL so any inbound links will maintain your page rank.) Eventually, you may have one page that is providing a lot of value to your business (e.g. has good click volume and a higher conversion rate than other pages). You can help prop up such a page by creating a linking strategy of having other less valuable pages link up to that one (and not vice-versa), then work on inbound linking to all of the above. This will bolster the "big" page, and ensure it is seen as most important to Google.
Inbound Linking: Inbound links are still the most important part of your SEO strategy, and still the trickiest to do right. Never employ gray-hat or black-hat techniques to get inbound links. The best links will come from content you write that is exceptionally compelling. Unstack has social sharing built in to your blog. Social links will help you get started. Link your articles on Twitter, Facebook, LinkedIn, and/or whatever community you think your potential customers use. Eventually, when you get big enough, seek to syndicate your content or write contributor content to other sites, with canonical references back to your original content or links back to your homepage. Syndication and guest articles will help you build your domain naturally in a way that's providing value to both you and a more established editorial site. There are lots of other techniques for obtaining inbound links (including many shady ones, like .edu scholarship hacks and text-link buying). Don't fall into these traps - they will almost always be found out by Google and result in penalization.