Story time! I am playing as the Vagalars on Hard difficulty.
As things usually go for me, I began by deleting all existing ship designs; I prefer to start with a clean slate. Suggestion: It would be nice if we could export ship designs so we don't need to recreate them every game.
I started a new Elliptical galaxy, spawning in the bottom left region. I began by queuing up 15 Colonizer Mk1-stand, designed with exploration in mind. As they constructed, I would send them out as far as they could go, exploring uncharted solar systems and colonizing a planet once their fuel ran out. I would later go back and colonize the planets between my home world and the outer boundary once I was a bit more developed.
For technology, I set Xenobiology to priority, then Hydroponics to priority; In my earlier games, I would frequently run out of food. I've made it my priority to avoid that problem. It also gives me a head start on unlocking Seismic and Radioactive colonizer modules and atmospheric domes, which will help with filling out my territory and padding my resource stocks early on.
I continued to explore, eventually meeting Gavakens to the "north" and Drills to the south, allied to each other. I quickly found out that I was boxed in by them, but I had carved out a respectable territory with a decent scientific base and good resource stores. I started to pay them off with any excess resources I had; I wanted to become good friends with them, lest I be destroyed on 2 fronts.
It took me quite a while, but I managed to get the Gavakens and Drills to give me open borders after dropping thousands and thousands of units of all kinds of resources over a long period of time. I began to explore out further, colonizing all unclaimed worlds I came across; It is my policy to colonize Exhausted worlds as Agricultural to help boost food production, even by a tiny bit. They can always be converted to industrial if needed.
Eventually, I encountered the Humans to the north, past Gavaken lands. They had declared war on the Gavakens and Drills, and I was more than willing to help defend my new allies. I began to pump out ships as quickly as I could, and directed research towards unlocking new hulls and ever-more efficient modules. I colonized planets in chokepoints between the Humans and Gavakens, waiting for the humans to begin demanding the planets from me. Once they did, I denied them until they were "forced" to declare war. This gave me enough time to whip up some ships for probing attacks, to get a grasp on what the human fleets were capable of.
I started with designing the "Cruiser carrier Mk1" ship. I created two, both loaded with 44 assault shuttles. The Cruisers themselves had little armament beyond defensive measures, but they were sturdy and fairly cheap. I sent two Cruiser carrier Mk1's to attack 3-4 (I cannot remember exactly), and while I lost the battle, I gained some valuable information: The human ships did not seem to fare well against the Shuttles I had designed, and my shuttles were not even armed as anti-ship.
Using this new-found information, I plan to develop a new line of carriers designed to cut into Human territory and fortify chokepoints in the warp lanes. They will regret ever demanding Vagalar stars.