1. Purpose of colonisation: economical - strategical
   
2. When to colonise: 25%: greens - 33%: yellows - 42%: filling up low-hab planets
   
3. How to colonise: in stealth - with speed - in force

• cluster control: You see a nice cluster of let's say 5 stars. The first player to establish a presence there, will most likely control the cluster and can keep other players away.
  
  
• claiming territory: If you manage to establish a cordon of colonised planets, you can control the space within and keep other players away. Afterwards you have the time to colonise the planets within. If you do it the other way around, those cordon or border planets may be taken by other players meanwhile, perhaps threatening even your core because they managed to establish a wedge into your territory.
  
  
• a wedge into (possible) enemy territory: Well, you can do, of course, exactly the same, colonising in a way that it is like a wedge into another player's territory which gives you a splendid future position to threaten and attack his planets. Since this might be not very much liked by the other player, make sure to secure such planets.
  
  
• denying an opponent the space to grow: This strategy is obvious when you are for example in the NW corner and then discover that there is another player located even more in the corner. Cut him off by colonising, shoot down his ships which try to break thru. Since you deny him space to grow, his growth rate will decline in comparison to yours. Soon you will view the cornered player as a fruit to pick at will (mostly when you have gained a comfortable advantage in tech and ressources).
  
  This tactic can be applied not only against players in a corner. Sometimes the same result as a corner occures due to several hostile neighbours.
  
  
• Gates: can have a mean effect. If, for example, you manage to establish a colony within 1-year travel time to an important enemy planet or even his HW, once you get up a gate, all of your fleet (which fits somehow thru gates) is actually just 2 years away from orbiting the enemy HW: 1 year for gating, 1 year for moving.

• hab value of planet
  
• capacity of planet or rather to how much it is filled up

pop    cap%  growth  growth%
250k   25%   47.5k   19.0%
333k   33%   50.0k   15.0%
420k   42%   47.5k   11.3%
500k   50%   42.0k    8.4%