So far as early military build up is concerned..... i have a couple of nice tricks for that;
When you set up your game, put minor races on 'abundant'. Then put tech brokering on.
During the game you can sell techs to the minor races, and when they don't have much money, you can buy some of their combat ships each time with your techs. The combat ships are very expensive but since they don't have enough cash for your techs, you really have nothing to lose, and i find all these ships add up allot over time and push my power rating way up.
The other thing that helps my power rating allot is to get a few more ships that can explore pirate anomalies. I usually look at whatever resource is excess and apply 1 of those prototype weapon on a medium hull along with prototype survey module and engines and i shield module and whatever range extension and sensors will fit. Also if i get free survey ships i like to upgrade these to this ship that can take down pirate protected anomalies. Once you have a few of these going, your defender type ships start pouring in from all directions.
None of this is much good for actual combat, but its all about your power rating to deter attackers.