Many of the same tactics that you will implement to increase conversions on your website are actually useful in improving your on-page SEO. In many ways, you cannot design your site for conversions in mind without also designing it in a way that helps its ranking within a SERP.
Landing pages should be designed in a way where the URL and the Title Tags are extremely close, if not identical, and the description used on the landing page to convince website visitors to exchange their information for your offer are contextually valuable from an SEO standpoint.
By creating a great landing page visitors are less likely to 'bounce' or leave this page and subsequently signal to Google that this page is valuable and should be regarded as such.
Optimizing for Dwell Time
Suffice to say that when a user lands on your site and then immediately decides that it is a poor fit for their needs, and then leaves, this is not going to assist with your conversion rate. What many webmasters do not realize, however, is that Google is also paying attention to whether people are fleeing from your pages at an alarming rate.
For example, if a user clicks a result in Google for your site then quickly scans the content and realizes it is not what they are looking for, then they will generally hit the back button and see if some of the other results are in fact more useful than yours. Google uses the elapsed time (or lack of return is even better) as a method of understanding the value of your site and whether it should be positioned higher within the results page.
The same processes that you will go through to try and drive more conversions on your site are the same tasks that you will complete to try and increase your dwell time.
Providing a Clean Experience Free from 404 Errors and Messy Redirects
Humans don’t enjoy clicking on a link only to find a 404 error telling them that the page does not exist, no matter how friendly you make your soft 404 pages appear.
The Google bots also do not appreciate being told that they got lead down the garden path only to have you tell them that the link goes nowhere.
Well Structured Content that Goes Into Depth on a Given Topic
You cannot begin going into depth on a topic without starting to branch out and using all sorts of LSI (Latent Semantic Index) Keywords. Both Google and your users will pick up on some of these more ‘peripheral’ keywords that you are using and interpret this as a sign that you have a deep knowledge and understanding of your subject matter.
The same way that you write engaging and useful content with the intention of having someone decide you can help them is the same way that you write useful content that shows the algorithm that your site will be a great candidate for a good position within a SERP.