1 Thou Shalt Keep thy code stupid simple (KISS principle)
2 Thou shalt not put queries in loops
3 Thou shalt utilize maps for queries
4 Thou shalt use relationships to reduce queries
5 Thou shalt not put DML in loops
6 Thou shalt only use one trigger per object
7 Thou shalt keep logic outside of triggers
8 Thou shalt have a happy balance between clicks and code
9 Thou shalt cover thy code
10 Thou shalt write meaningful unit tests
11 Thou shalt write unit tests before developing
12 Thou shalt test all conditions
13 Thou shalt never use dummy code coverage
14 Thou shalt never test with existing data