Often, companies create Landing pages and then expect it to perform as it is. There are actually many factors that will make a landing page work, from design & UX to SEO.
Users need to easily understand your website. They should be able to find what they want in a heartbeat. They should know where to click and how to navigate through your site. Check how the page fits within the website, does it make sense in the customer journey? A beautifully designed website is nice, but you should definitely make it your top priority to create a user-friendly website first.
External and Internal Linking
The importance of the page should be measured by two main parameters: how deep in the website it is (the more important the keyword the page is targeting, the fewer clicks it should be from your homepage), Secondly, the more important it is, the more internal and external links should be pointing to it compared to your less important pages.
The keywords you have selected for the page as the most important should be used for content and general onpage optimization. Make sure another page is not cannibalizing the traffic for the selected keywords(s) and organic traffic is not going to another page instead of the one you chose.
Generic technical issues also apply such as page speed. It needs to load fast and of course be mobile friendly. Finally, the page should be available for indexation and crawlable.