Here follow five basic keypoints on quality building, open to debate
1. Coherence.
A building should have structure and textures coherent with Sim's theme.
2. Usability.
A plot should guarantee prims enough both for building and furniture.
3. Structural Perception.
An Avie should feel at ease hangin around in a building (limit narrow spaces and low doors)
4. Texture perception.
If texture's resolution is higher than 512 u get troubles. Too much use of alpha textures (atm) get troubles too.
5. Look and feel
Have in mind overall "emotional impact". Why did Lindens invest so much in the new viewer?