Hello, so I have seen on the forum a few threads saying that winning vs suicidal AI is too easy so I decided to test it, and share some tips, tactics, and what AI could have done smarter.

So far, it is turn 150 and I am winning, in a large galaxy with abundant stars and hab planets, and occasional relics. It was not 'easy', because I had a bit of luck and AI played their invasions ineffectively.

I have created a custom race with the description "Like the zerg, they try to outproduce and swarm everything".
Abilities : Patriotic, adaptable

Traits: Productive+2, Clever +2, Content+1, Fertile +1, Klutzy-1, Dense +2, Militant+2, Unpopular-2, Poor traders-2, Farmers+2, Gentle-2, Craven-2, Tough+2, Inaccurate-1,  Clumsy-1, Brittle -1,  Unadventurous -1, Likeable +2, Organized +2

Their homeworld is Q8 +Q4 + Q4(maximising the number of tiles with the homesystem was the idea).

Thalan tech tree.

12 Factions, 8 vanilla, 1 random and 3 of my custom ones (which, I have to note, were not retarded )

This setup should give an edge in production and when fighting in large fleets with enemies you choose (likeable makes it less likely for you to get attacked). I have found that picking the combat handicaps has no significant effect with a  bit of tactics.

I started the game near the edge of the map (best start i believe)

At the beginning and through the rest of the game I moved the govern slider to 50 50 research/prod. Though now it is 45/45/10. 

In the beginning- grab as many colonies and develop them- pretty standard tactic. Purchased dual factories in the capital and a colony ship. Most of the colony ships are filled with 0.8b pop. Colonized the first planet, got 3 ideology constructors which were turned into colonizers. Second ideology was benevolent free colony ship.  As new colonies are founded, they immediately begin sponsoring the home planet shipyard. Near the end of the colony rush i have managed to make a small hull colony ship that was constructed twice as fast as normal ones(though, I have only managed to get them to extreme planets)

Researching the hive, planetary clinic, approval bonus from the trading tech and speed engineering. I have managed to get around 10 colonies, none of which are Q15+, and my neighbours are Yor, Drengin, and a benevolent custom race. Wonderful... After 15 ish turn I can see that I am being swarmed by yor, drengin, and Norimi(custom race) colony ships... There were a few Q5- uncolonized worlds that got in the hands of the other races, with drengin taking the 2 planets in my home system. I thought  I could easily culture flip them but that turned out not to be the case . I also managed to get 2 or 3 tier 1 extreme planets. All in all, I have managed to unlock the 50 turn nobody attacks you ideology ability and missionary centres. I have completely ignored mining starbases and my territory was littered with foreign mining starbases. 

At this point, in the power graphs, Yor were 2 to 3 times ahead of the second on the list who were... Drengin... Both my neighbours. This is of course not to my liking. At this point I had about 40 turns of guaranteed peace. I decided to rush buy hives everywhere and have managed to get 3 shipyards that are reasonably productive. In the next fer turns a few economy starbases were constructed around planet clusters, and an influence starbase in an attempt to culture flip the drengin out of my home system.

It is obvious that Yor are going to be a problem once my free peacetime expires, so I have sent my survey and explore ship in their space to scout them. Their home system is extremely close to another system with 2 Q15+ and 1 Q9 planets. I am jelaous .

So, how to deal with the powerhouse such as Yor ? Get the whole galaxy to go to war to them that's how . The cheesy tactic is to go tech-trading and at the same time ask them to attack the YOR (to jumpstart this, I have first asked Yor to attack the drengin). After the tech trades, I have managed to get to a third place in tech. Important note, i was getting negative income so i had to tech trade for money too... Until now I have been researching mostly planet development techs(my planets were low to medium quality) But now i had the chance to rush photon torpedoes and large hulls (defenses were almost completely ignored, in tech  trading too). Around turn 50-60 I had started building transports and warships in preparation to blitz the Yor. My ships were small 30 damage missile boats and medium 60 damage frigates(no defenses). Yor had battleships with over 80 missile damage.

Around turn 70  I have managed to build and fleet  5 large 80-100 missile battleships, with a secondary fleet of around 8 or 9 smaller ships, which were supposed to protect 3 transports going for the yor home system. Another transport was within 2 turn range of another yor undefended planet in my terrirory (though it has its own influence bubble, I've managed to culture flip another planet in my influence, 30 b population boost definitely helps with... everything [even if that meant i had to prioritize farms and offload transports to fill them with ex-yor soldiers]). My fleet also consisted of 8 triconstructors (constructors with 3 modules), With the intent to build a military base in their home system.

So, the invasion begins, my A battleship fleet, along with the constructor fleet and 3 transports are racing through yor territory to their capital system. One transport is parked near their world in my territory while my B frigate fleet is making its way along with a troop transport to another border world. The time is of essence since my 50 turn free peace will end anytime soon(or has already ended). Yor fleets are strong and numerous. Even though my battleship can 1 on 1 a single yor battleship, they have dozens of fleets, though they are occupied waging war on 7 fronts .

Also of note is that i had to trade for around 6000 bc in order to use biological warfare on the 30b population yor planets (heh, should have invested in an antivirus). 

On our way to visit their home planet(cca 30 parsecs inside their territory) a military base with movement speed boost was built(also to extend range)

BANZAI!!!! Could be heard all over the yor homesystem and the system closest to it. Yor have intelligently decided to keep their 400 production strong planets defended with an armada of two really low tech ships. In a single week, a military starbase which makes my  missiles more effective was built, their homeworld was taken, and their emergency second homeworld has also fallen just moments after, using cruel biological warfare tactics. Now I have acquired 2 Q15+ developed planets and starved them of around 800 hammers. In the same week, two more planets have fallen, the one in my territory and one on the border. Because of exploration treaties, I knew that their main fleets were more than 50 parsecs away... Though their fresh fleets are not to be taken lightly either... In the second week of the war, their fifth world fell, this one also Q15 , only one more remained. This blitz ensured that their most productive systems were effectively conquered... Though retaliation party came a few turns later, and it was MEAN. it immediately took back one of the planets and managed to decimate my fleet(I am not joking about decimation, it survived, though with only 2 ships remaining... fresh reinforcements of battleships and carriers were on the way though). Fortunately, yor fleets were busy moping up other races in their territory. What ensued is a tug-of war for the control of their homesystem. Nearby planets got switched a few times, but I have managed to come out on top eventually, even though they had fleets that could destroy mine, and were also faster than mine. Why ? Because they were garissoning planets and having offensive operations on another front... Which allowed me to destroy their shipyards and pick off their battleships one by one. However, Drengin were using their 2 planets in my home system as staging grounds... and declared war on me shortly after. My ships were more advanced though, and after the initial takeover of two of my border planets I had managed to raise a fleet and destroy most of the drengin military presence in my territory.

At this point, yor are a shell of their former glory (I have taken half of their planets, and all of the good ones , and are only occasionaly sending a war party (technologically advanced though) with no transports in their home system, which were consequently repelled). Most of the galaxy was 'persuaded' to join in on the war with the drengin...

In the next 50 turns, both Drengin and Yor are destroyed. I am now 4th in the power graph, with Krynn and other 2 of my custom races in the 2nd and 3rd place.

By this point, My colonies are very developed and I am first in pop and tech(can't even trade anymore). I will play this to the end in the following days probably

But for now, yeah, AI did make some mistakes, mostly not recognizing which fleets are important (my fleets which were essential for the supply of transports were largely ignored when there were easier pickings of some other races that were not accompanied by transports), it left their most important planets (500 hammers !!!! ) virtually undefended, and the Drengin declared war too late(if it was 15 turns earlier, i would have had a real problem...)

Free 50 turn restrictions of AI not going to war with you effectively enables you to park your fleets near their most important planets and blitz them