Colonization is a vital asset to the game. Doing this is will added a more crew to the crew pool. There are different ways to colonize a world there are advantages and and disadvantages to colonize. If you come across and enemy colony and wish to take it over the colonies there are different ways, the Federation with its tradition of a none aggressive way prefers to use assault ships (Iwo Jima class vessels) if you select the Transport attack you send a group of mercenaries to attack the enemy soldiers on the planet without killing the other people on the planet and destroying buildings. Other races would like to bombard the planets to do this you need a battle ship to come within weapons range and then multiple attacks hit the planet, this causes buildings on the planets to be destroyed, the planets civilization will start to die and the enemy colonists will be killed.
Once the enemy colonists have gone you can transport soldiers from a ship and take over the colony. Or you can use the more efficient way and that is the colony shop this will send its crew on the planet and the ship gives the crew supplies depending on what type of planet they are. Something else can happen to the planet you are on and that is that you can make special type of defence a planetary shield. This protects the colony as long as it is stable. When the shield has been bombarded the colony will be open for take over.