There are some parameters on which you can align your landing page.
- It should be in synch with the ad that directs to the landing page.
- Provide the promises you made. (Since, this is the reason why they are here. Why annoy them?)
- Let it be impressive.
Here we have some tips for a perfect landing page.Checkout for more: http://acodez.in/ux-designer-tips-for-landing-page/