Please follow these rules when building on ruined:

No tunnelling
No castles
No models, 3d/2d figures or the alike (build these in the recentmost builder map)
No lavapits
No huge-ass signs
Stick to the theme (modern urban environment)
Try and make your buildings aesthetically pleasing on the exterior. If a building is not up to standard within a reasonable time after construction has begun, super ops may decide to destroy it (at least 3 super ops must agree on destruction)
Construction on reserved slots must begin within 24 hours of reservation
The building must have aesthetically pleasing exterior within 24 hours after construction has begun
Don't make roads leading to places that already has a road
When making transportation that already exist (roads, metro, tunnels, etc.), keep to the existing design
Do not couple of with other people's buildings without their permission
Do not try to improve other people's design without their permission
If a building is left with no interior for more than a few days, the owner forfeits the right to design the interior. Other people may then design as they see fit (exterior must remain as it is).