Good code is modular, and time and space efficient.
Meaningful css class names. Semantic if you can be. Reusable classes.
Make sure that the page is ordered into understandable parts (in regards to accessibility).
Can be a symptom of a bad dependency. This means that something (perhaps a class) in your code is inflexible and unstable. This will make your app hard to maintain in the long run.
Switch statements can be better if you’re checking for a row of specific values.
When things get bigger… use a hash table or something similar for lookup.