Being fairly new to the game, I struggle with really building much in the way of ships as I am always waiting for just one more tech. I think I should just SM what I want and go from there . I generally start conventional and research and build from scratch. For the more experienced, are there general tech epochs or "levels" you aim for for different things (armor, engines, weapons, etc) being that there is so much to research? Or do you just wait and see what you encounter first? Since I start without TN tech, I set non-player races to 0. I'm assuming that when I explore, they will spawn at my tech level?
I think Aurora is more grindy that you think. Especially now that you can easily deal with 50 to 70 systems in the first game hours building is the key.
As your production should always bu busy building at 5% all most important structures such as construction factories, automines, research labs etc with accasionally boost of single important projects so your shipyards should be always busy in expanding capacity, slots or building ships.
If you play without NPR at start (as I do) you actually need more ships as the NPR generated after will have strenght based on a formula that will consider not only your base tech and population but also the time passed since start.
You could soon find yourself in the unconfortable position of simply not being able to close the gap with your opponent assuming he is hostile.
Remember that NPR here play same rules as we do, when they discover you they have 0 intel and if they see 100 ships in the system they may back up even if they are technologically superior. This means also that speed is very important as the AI might decide to take its chances if it thinks he can outrun you if things go down the drain with a first strike.
Also release new classes after having been spotted as well it's a good idea to keep the AI on its toes with intelligence.