[TurinTurambar]

OK giving away the secret here to always having a larger population than most, but the Repeat Orders button is the key, so here goes.

Auto load and auto dump of population from your starter 2K worlds with a small, slow transport (or maybe a Destroyer hull if you wanna keep it under 200) to your largest Breather; a 4K or 8K. Once that is full, shift the convoy further out into your systems and add ships of the same type to quickly populate more outPosts. One 8K breather can build pop on several smaller worlds with an auto-convoy of 3 or 4 shuttles.
The danger of course is "raping" your starter worlds and under-populating them, thereby hindering production and reproduction. The key is "small and slow." If your first large breather is in the next system over, or you're starting with only one planet, you can slow things up by using a smaller hull, pulling an engine off the Design, or sending the convoy through an extra system or two in its route.
By turn 60 or 80 of most games I've got 10 or 15 convoys going and I don't even have to think about it, especially since I retrofit the lil buggers with cloaking devices later. And everyone else is saying "Leonine? Your guys look more like rabbits!"

As far as new discoveries: The System Notes window is a fantastic little mini-database of my galactic explorations.