I've only played this game a handful of times. Each time I have dominated the AI by the begginning of the middle techs.
This last game I started was the first Challenging one. I had, in the past, used a scout ship with a survey pod on it to gather as many anomolies as I could (since these buffer your economy during the colony expansion phase). In this last game I designed my "trash can scout"
You need impulse engines and sensors up ASAP for this to work. Take a cargo ship, slap a little support for range, a survey mod on it, and as many engines as you can fit.
You take these suckers and send them out to the four corners of the galaxy, picking up every anomoly you find. If you find a resource, upgrade to a constructor and grab it, if you find a 10+ planet that you think fits your desires, upgrade to a colony ship and colonize it. The advantage here is that this 'trash can scout' will be considerably faster and as long range as either a colony ship or a constructor, plus it can pick up any anomolies along the way.
If you do colonize with one of these trash can scouts you have to send a colony ship there to back it up. You only start out with ~10 mil people otherwise, and it will take forever to get to a viable colony otherwise. The point is, however, that you got there first. This early in the game your only real concern for someone taking it now is spore ships (which is a real concern).
This is an expensive thing to do, and the amount to which you can do it depends on how many cash anomolies you find. The upgrades cost you a ton of money, and any planet you colonize with a trash scout will automatically be in the red (since there are so few people). It will also be hard to balance the economy as you get these places started up. No point in putting anything but a couple trade centers on these planets, and don't buy any upgrades (unless you find a precursor library or something).
This worked amazingly well in my last game where I was surrounded on all sides with only two systems to work with. These scouts quickly found me a corner of the galaxy that no one had seen yet, which included a nice class 26 planet and a number of high resource worlds.
Anyways, wondering if yall do anything similar. I definitely think that using small scouts is a complete waste as they can't be upgraded to take advantage of that economic resource you just found halfway across the galaxy. Plus, you can fit way more engines on the trash can scout.