To colonize, you need to first build a colony ship. To view the requirements for this ship, and other ships, you just need to click on Technologies under Empire Menu. Green ones you have, red ones you have not fulfilled.
Once your colony ship has finished, you colonize a new planet by finding a planet that is not owned by another player (click galaxy, scroll through the systems and galaxies and any slots 1-15 in a system that do NOT have a planet and player name can be selected).
Next is the colonization mission itself. You send this similar to sending transports or attacks. Click fleet (under player menu), type 1 in the colony ship opening, select continue. Enter the co-ordinates you wish to colonize ie 1 1 1 planet (you cannot colonize a moon as moons are formed from battles), you may or may not need to lower the speed to save on fuel. Select continue. Choose the mission as colonize. Do not take any resources with you. Select continue.
As for planets and strategies, here are a few:
Unless things have changed (someone please correct this if true), slots 4-9 and slot 14 give, on average, the largest planets (most fields). Do not keep any planet under 250 fields, and you may even want to up that number to 300 depending on how much infrastructure you want later. The reason is that as you fill the number of fields, you can only get more through terraforming, which is expensive.
Slots in the lower planet slots (ie slot 1) of a system give warmer planets. Slots in the higher planet slots of a systems (ie slot 15) give colder planets. Warmer planets give a very noticeable boost to solar satellite production. Colder planets give a slight boost to deuterium production. For those reasons, I prefer slots 4 and 14 (just my preference, though I am sure others have their own).
Now for where to colonize. A general rule is to spread your planets out. This gives more raiding targets and makes you harder to chase down later on in the game.
An
old colonization thread, but with pictures:
viewtopic.php?f=17&t=316
Death begins with life's first breath, and life begins at the touch of death.