Best way to double park's value?

Hey all... 

I'm trying to beat all of the RCT, CF, and LL senarios (no trainers), but I look at the goal of "doubling a park's value" and i am stumped.  these parks dont seem to have enough room to do anything.  Can anyone offer some pointers on the best ways to double a park's value?

Thanks in advance.

if ya keep adding big expensive coasters then it goes up
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Out of the coasters i've ridden here is wat i rank them overall:(ive been to canobie lake and SFNE)
1. S:RoS 2. Yankee Cannonball 3. Riverside Cyclone 4. Canobie Corkscrew 5. Thunderbolt 6. Galaxy 7. Mind Eraser 8. Dragon coaster 9. poison ivy's tangled

Make sure there's enough room, lots of toilets, theming ect. Try to make the park lóok nice

Raise prices, add as many rides as you can, and not just any ride that comes up, rides that you know are money makers, like coasters, towers, enterprise, thrill rides, and a couple of gentle rides like mini golf.