My guess is you're either letting your games take too long, in terms of turns, or that you're not building a very large military-probably the former and the latter may have some impact as well.

Something you should understand, though, is that virtually all scores over ~100k-150k are done almost entirely for scoremongering purposes-they don't play out quite like a normal game does.  (The ZYW is an exception in a sense, but as it's done for most points per real time investment, it doesn't really count as one.)

If someone wants to correct me on the lower threshold where scoremongering makes itself apparent, feel free.  I'm also not the best guy to give you tips on increasing your score, but if you provide more information (for instance how long your games take), I'm certain others can point you in the right direction.

Not that there's anything wrong with playing for score.  But, for what it's worth, if you're winning, why does score matter?

I noticed a lot of your games were won by peaceful means. They way you win also determines your scores greatly. Because you had political and cultural wins i'm guessing you didn't have a very large military or had many battles. War is one of the most efficient ways of raising your points. A military victory gives you the most points because it is meant to be the hardest to achieve. the more you fight the more you get, Thats why evil races have all the fun  .

try playing a game for a military victory and see what happens.

The most important key to a higher score is to do everything faster.  Get your mil rating, population, economy, and tech output up as high and fast as you can.  Take advantage of points-grinding techniques if you have the stomach for boredom and monotony.  Never end a turn with your treasury above 20k even if you are just grinding, because your econ score will take a huge hit.

Sentient species taste better...

Or just reloading at need, which is how they hold an econ event for years at a time.

Either the Re-Education Center or just let the enemy have 2 planets. One of them being some worthless PQ 4 piece of rock. As soon as one flips, give it back.

Once I completely relocated "the other race", too. Gave them 2 planets at the edge of the map along with the 4 influence starbases I prebuilt in that sector.

They totally owned that space and I didn't have to worry about them any longer. Their original colonies eventually flipped, of course. As they should.

Sometimes I build eco starbases for them, too. To boost their research so I can steal more useful tech from them. A handful of constructors means nothing at that stage.