From the get go you need to improve Titanium for its production. If you haven't got a worker, build one and mine Titanium near your first city ASAP.

In order to see Titanium you will need to research Engineering or choose the Tectonic Scanner spacecraft loadout when you start your game.

Next, you need to expand rapidly and build at least 5 or 6 cities that exploit Titanium.

To build colonists you will need to research Pioneering or have the Laboratory cargo load out when you start the game.

After you build your first colonist, I recommend building a Trade Depot. This will allow you to next build a trader, which you can use to speed up the conversion of your outposts into cities.

Affinity is what determines the strength of your units. The more affinity you have the stronger your units will be. They will upgrade instantly and have access to additional perks or bonuses.

There are several ways to ramp up affinity:

1. Exploring - Send Explorers to excavate Progenitor Ruins, Progenitor Devices, Alien Skeletons or Kraken Nests.
   
2. Technology - Research. Look at the technology in the Tech Web to see how much of which affinity you will gain by researching it.
   
3. Quests - Completing affinity quests will grant boosts to affinity. (Don't ignore these).

Watch your neighbours affinity progress. Try not to be too far behind them. AI will especially war if you fail to build your military.

Ideally plan to get to 6-6 affinity.

This is known as a hybrid affinity. It's when you have 6 of two affinities. (It doesn't matter which two).

Civilisation is all about conquest. You cannot avoid war regardless of your disposition.

The endgame is about getting to 8-8 affinity.

While you are ramping up affinity, build Combat Rovers. (Land cities get bonus production towards land units). At 8-8 affinity these will become hover units, able to conquer land or sea.