By recruiting units and getting workers.
10 infantry - 1 power
10 vehicles - 2 power
10 tanks - 3 power
25 workers - 1 power
I recommend buying reds and voting at this link every day
http://www.battledawn.com/?p=vote so you can boost for workers regularly.
Also, be very active and make smart decisions. And stick with one unit chassis. Here's my build
Infantry - 10 armor, 10 damage and 10 range in each squad
Vehicles - 5 armor, 5 damage and 5 range in each squad
Tanks - 3 armor, 3 damage and 4 range in each squad
Good luck. If you have any more questions don't hesitate to ask.