Using a clever solution is better than using a brute force solution. It's always worth expending some effort to keep your code clean. Try to avoid over-long functions and routines, steer clear of deeply nested control structures as much as you can, etc. For instance, use several small routines rather than one very large one. It's easier to read, and easier to debug.
Premature optimisation is the root of all evil.
Get your program working before you try to make it go faster. There is a balance to be struck when writing comments for a program. See below for more details. Use whitespace to lay out your code and improve readability. If you have a large procedure then it probably falls into several logical units.