Above the fold

On a phone this is a small space: often one headline, one line under it and one button. Most visitors decide in that space whether to keep reading. So it must say what you sell and who it is for.

Put your value proposition in the headline and one clear call to action right under it. Then open your landing page on your own phone and check both show without scrolling. A high bounce rate often starts with an unclear first screen, so write the headline before anything else.