If I have a mantra, it would have to be "Is there anything redundant here?". Along the same lines, it is "How do I split this into reusable parts?" (which avoids redundacy from the get go). And what I'm always concerned about, "How obvious is the intention of this code?" - I try to pick identifiers such that the code almost reads like English, both for my own sake if I return to my code 2 years later, as well as for that of anyone else who might look at it. I try to melt code down as far as keeping it self-documenting will allow. (Statement modifiers help a lot here.) Maybe I should say my mantra is "How do I make this beautiful?" :-)

Makeshifts last the longest.