According to this infographic from Bowler Hat your landing page should start with a strong headline. It needs to engage your visitors and convince them to read further down your page.
Next up is a clear call to action where you tell your visitors what they need to do next. This would normally be a button that links off to your contact page.
Most visitors will need to see more before they commit to contacting you though, take a look at the infographic to see what else your landing page should include.