The default is that everything sorts alphabetically - obviously that doesn't help if you are trying to sort months. Custom lists can be quite useful- give it some thought.

Grouping

Grouping is just such a cool feature and for some reason Microsoft Excel doesn't really discuss it. Grouping allows you to select multiple sheets at once and anything typed on one is automatically recreated on the other sheets. This is a big timesaver.

Watch Window
This is a great feature if you are working on complex sheets or files and need to keep track of certain values.

 You can tell Excel to watch a calculated value on Sheet 2 and then move to another sheet and change a value there that impacts the watched value and the Watch Window will show you the new value without you having to flip to that sheet or file.

• Right-click on the cell you want to watch and select Add Watch.
•  A window will appear and as you select other sheets and/or files you can keep track of the selected cell(s).

Tip:  If you are watching many cells it is is easier to keep track of them and their changing values if you have given them  range names.

Remove Duplicates
Tired of sorting data, looking at it and then deleting duplicates? If so, check out my video clip on Removing Duplicates in Excel 2007