Micromanagement

[LDiCesare]

Only produce units at forts. You'll be unlikely to have 50 forts on any decent sized map for SP until you've won the game.
And put some victory condition like VPs, you can teleport/cloud trapeze and take them all from the ai when you reached the point you should have won but can't continue due to the hassle.

[MaxWilson]

Sometimes I take a cue from the original Master of Orion 3 plans (which were later scrapped) and say that I, my pretender, only have so many "attention points" for giving orders. My mages will forge only five items per turn (all the others will do research by default). I can order only five attacks per turn (although it's okay for an army to sit there and defend, or to maneuver prior to an attack). When I'm in a dominant but not yet superdominant position, it doesn't hurt much to delay some attacks until a later turn, and I don't have to deal with trying to juggle five parallel military campaigns in my head. Basically, some armies have to get ignored temporarily even though they're militarily capable of making progress because I don't have the cognitive resources to manage them--and it's thematic!

I also agree with victory points. At a certain point you just want to cast "Master of Magic" and be done with chasing down tiny provinces, so I give a roleplaying reason for the victory points to matter (shards of the Pantokrator's power) so I can feel like it's really OVER when I get them and the game ends. "Having conquered the worlds of Arcanus and Myrror, you are now the one true Master of Magic!!! <fireworks>".

Oops, I mean "Having retrieved all 13 shards of the Pantokrator's power, you are now the one true God!!! <fireworks>".

-Max