On average, five times as many people read the headline as read the body copy. If your headline doesn't land, the rest of your page never gets a chance.
A strong headline does four things: it calls out the audience, promises a specific outcome, hints at the mechanism, and removes a fear. You don't need all four every time, but the more you stack, the harder it pulls.
Specificity beats cleverness. "Get more leads" is forgettable. "Get 50 qualified leads in 30 days without running ads" is a promise people can picture. Numbers, timeframes, and the words 'without' and 'even if' do a lot of heavy lifting.
Write ten headlines before you pick one. The first three are always the obvious ones everyone writes. The good one usually shows up around number seven.