[Endoperez]

I usually use victory points. Take few enemies, give every capital a vp, add enough single-vp provinces to double or triple the number of vp's (so you don't know whether that vp is a capital or just a vp and so that there are enough vp's on land), and put the requirement to 50% - 70% of the total vp's. That means I have to conquer most of the map, but also that I can end the game quite fast if I decide I really want to.