The first things I built on my colony was the farming and tech mining. 30 days later and I was already at 5% of the food production market with a size 3 farming colony. That's pretty darn goofy.
Anyhow, a couple months later and I was already getting expeditions sent after my colony. I could bribe them away for 100k a shot, but that was more money than I had to burn on something like that. Now I'm up to size 4 and $135k/mo and we're receiving expeditions regularly (but not back to back, per se). Basically I just go exploring for a bit and keep an eye on the countdown and rush back when necessary to fight them off. Unfortunately the defense fleets and pickets are pretty useless at this point. They can pick off the stragglers but I don't trust that they're big enough to properly defend the place so I don't even take the chance. If this was Nexerelin then I would just invest in a few defense fleets OR if I could just leave a bunch of ships around to serve as the defense fleet then that'd be awesome too. It's not clear what I am supposed to do to get a defense fleet that actually has some meat on it. I've unlocked the plans for a few big capitals/carriers but they're not being used.