In paid search marketing, the difference between a profitable campaign & a wildly profitable campaign usually lies in the conversion rates of the landing page. Which is why you must keep testing till you get the highest possible conversion rate.
Bear in mind that pay per click visitors that click on your ad are not stupid, they know that they just clicked on an ad. That is the reason why they might be a little skeptical & you only have a very short time to capture their attention which is why your landing page must be really compelling for them.
Strategic Keywords
Place related keywords strategically on your landing pages. Do it naturally instead of stuffing them all over like some spammer. Keywords must be found in your title tags, description tags, meta tags, keyword tags, H1 tags & sprinkled naturally all over the page.
There should not be any broken links on your page because you will get penalized for it & it also gives visitors a poor user experience when visiting your website.
Loading Time
The loading speed of your website must be very fast because in this day & age, nobody is patient enough to wait 7 seconds for any website to load. You can fix this by cleaning up your HTML code, if you are not familiar with it, you can hire someone to do it cheaply since this is a very simple task.
Business Links
Add a few business links such as a contact page, privacy policy, terms of service, about page, disclaimer. At least, you must have a contact page & a privacy policy page. Put these links at the bottom & make them smaller so that visitors will not get distracted by them.
Get your visitors attention with your headline, show them the most compelling benefits & tell them to take an action now, not today because today can mean 12 hours later which they would not remember you by then. Once again, take action now, not today!