Gigantic galaxy; difficulty: crippling; Altarian Resistance (light blue, screenshot minimap), pacifists party, Super Organizer; 9 races; 8 minor races; planets: occaisional, many inhabited (I think).
Strategy which developed: destroying enemy mining starbases, spy-sabotaging non-factory buildings, diplomacy, "choosing wisely" to pay money extortion demands/help requests, much rush-buying.
In the screenshot, Altaria is in the centre and there is a group of 3 planets (one was PQ 22) near Thalans (pink) and Toria (green) which I discovered unclaimed during the colony rush stage. This happens in some games (whole unclaimed star systems near alien colonized planets), so early on I often research or trade "ion drive" and build 3-speed colony ships with llife support. Even so, I was surprised to be able to claim all 3 planets so close to Toria.
About 5 years into the game, I had made a very good economy (I don't know exactly what it was that I did right and I only had one mining resource, moral) which I used to bribe races and rush-buy or upgrade even my huge hull ships later; I also rush-bought the re-education center on one of my planets.
Korath (dead, at the screenshot, originally in the red Drengin region in the minimap) were the strongest and seemed to be ready to declare war. My military was fairly weak but my diplomacy was good so I had been researching or buying/trading diplomacy techs; most races were evenly strengthed so would, I guessed, be ready to join any side in a war.
Korath declared war; I bribed some races to declare war on Korath, however I was not happy to contribute to their galactic conquest funds (e.g. Korx, light grey in the screenshot, who tend to declare war easily against the Altarians when they are strong). I traded diplomatic translators from Yor and built the galactic showcase; mainly hoping to bend other races to my will. I would have to monitor other races becoming weak and therefore susceptible to extortion from non-Altarians (e.g. Yor in the right-hand corner).
Korath were defeated, but Korx were becoming hostile so I was preparing my defences and monitoring the diplomacy and treaties screens. When Korx declared war, I was evil alignment so the Torians would not be as easy as they usually are with the Altarians. Screenshot: Krynn, Yor, and Drengin had decided to help me. What to do about Torian and Thalan?

The treaties screen shows Thalan being hostile to Korx, and close to Krynn; seems good to me but they declared war against the Krynn! The next screenshot shows how I changed that with a "make peace" and "declare war" deal in one, and so cheap. The Thalans would find the gravity accelerators and micro repair bots useful in their valiant battle against the Korx. If I was going to win this game, it would be via my diplomacy and large treasury although I had to be wary of these evil races deciding that someone is conquering their food or that it is time to exterminate the weak. The Torians declared war on the Thalans because of their "unprovoked attack" on Korx (hehe).

The Korx military was large but their firepower was concentrated in relatively few ships - they could not get everywhere and surely they would take a long time to build such costly new ships. Near the centre of the Korx region, one of my planets had an orbital fleet manager. I was rush-buying large hull ships on several nearby planets so that they were all built on the same turn and could get to the OFM planet in the same turn. I destroyed their 4 moral mining starbases near the top-right edge of the map; I had a ship there ready for this war.
Eventually Korx were defeated. The light-grey area had become mine. I had captured the galactic privateer (so my trade ships could help diplomacy while having a line of sight through warzones) and bazaar, and my spies had stolen the aeron missile defence (the ultimate ship missile defence); I could and would rush-buy many ships (even huge hulls with doom rays/blackhole eruptor/aeron missile defence/ultimate shields) without having to wait for building-time. Somewhere high in the missile weapon techs, more powerful weapons are not better on a cost per attack value basis, but this efficiency meant nothing when my ships were still being defeated.
Now was time to let my newly conquered planets build (mainly stock exchanges), constructors to develop my new mining resources, and perhaps make some fleets and military starbases. Drengin was strong at this time, so I made an alliance with them while they were "close"; they tend to become less friendly with the Altarians as they become miltary stronger. Risky, they like starting wars with anyone and the Torians have their historic hatred for the Drengin.
Drengin declared war on Krynn and the Torians declared war on the Drengin and I had to honour my alliance. The Thalans joined in the fun with us but Krynn joined the Torians. The Thalans conquered most of the Torian planets (green region).
Soon after we had won, the Thalans suddenly declared war on me! Drengin helped me as an ally and Yor decided to help me. As this stage, it seemed I was heading for a political victory (Altarian-Drengin-Yor, I had only recently allied with weak Yor because too many races had attacked them), only the Thalans to defeat.
Rush-buying transports and huge hull ships, I didn't need to have a ship on all my planets all the time. I put 35 spies on the Thalan planets. I had earlier put about 20 on the Torian planets (including ultra spices goods, restaurant of eternity, Xanthium hull plating, virtual reality centres, political capitals). This war was not as chaotic as previous wars in this game when there were fleets of various races changing alleigance all over the map and transports trying to sneak through it all.
When the Thalans surrendered, I won the political victory and also had influence victory "in 10 weeks". Final score: 30430, game time: 11 years; alignment: evil.