This is probably known by everyone, I am a late bloomer...
It seems that the first planet is always the highest the planet can sustain for mineral and quality. For instance, if the planet is 8-26 Quality and 2-20 Mineral, your first colony ship (start of game) will always start with the max of each.
Is this the case or have I just been extremly lucky lately and paying more attention at the right time?
Anyway, this leads me to think that it is more of a strategic planet selection that can make lower worlds more profitable. So rather than always selecting a high yield planet it may be better to select a lessor planet and maximising it, saving the better planets for later aquisition.
I've successfully used the strategy giddion suggests. Use the three starting colony ships to get maximum values for systems with lower quality/minerals. This allows you save higher quality systems for later colonization when you'll get a roll. The main advantage of this approach is minimizing the chances of getting a very low quality system early in the game when it can cause a lot of problems.
There's another thread on this around here somewhere. In that thread, Cory mentions that this strategy can lead to problems with your prime colonies becoming overcrowded/overpopulated in mid-game as your tech is not advanced enough. I've avoided this by advancing the colony side of the tech tree substantially faster than the ship side.
The few times I've used this strategy, I've mixed it up--some primes on low quality systems, others on high quality.