After planetfall, I focus on food to knock down growth by one turn, then build colonist with laboratory (free pioneering tech) which usually coincides with engineering finishing up to reveal titanium (major production boost). Retrograde thrusters and artists help. The former with revealing potential settlement locations and the latter for prosperity development. Build another colonist and by the time your second one is done, you should be able to receive a free colonist via prosperity.
Make sure to purchase production tiles and forgo food tiles since your pop stagnates during colonist production. If you manage a free worker virtue, cut down those trees and build mines to increase colonist production speed. Since you make landfall first, it's arguably easier to land grab from the AI (especially if they land close to your capital) earlier than later.