[internet101010]

For a best practices introduction I would recommend a course geared toward investment bankers. Some things that should be covered are:

* Avoiding hardcoding numbers, making input cells a certain color, etc.

* Knowing the all powerful F4 key that alternates between A1, $A$1, $A1, and A$1 (and knowing what each of these mean)

* Inserting blank lines above and below a summed range and including those rows inside of the sum formula (prevents formula from breaking if you move rows around)

Other than that you can do a lot of productive things with a combination of index/match and dynamic named ranges via offset formula.

[throwaway2037]

All solid advice. I learned many of these by: (1) reverse engineering other people's great sheets (formulas and VBA), and (2) watching highly skilled Excel users.