My most commonly-used Excel keyboard shortcuts and tips

There are a lot of sites where you can find Excel KB shortcuts (URL) and tips (URL), but these are the ones I seem to use most. They should make you much quicker in Excel.

Add a row

shift+space to highlight row, then ctrl+shift+'+'

Delete a row

shift+space to highlight row, then ctrl+shift+'+'

Add a column

shift+space to highlight row, then ctrl+shift+'+'

Delete a column

shift+space to highlight row, then ctrl+shift+'+'

If you're in Office X or forward you've probably already figured out that when you hit "alt" you're shown the next key to press to reach ribbons and menu items within ribbons. Here are the ones I use the most.

Add a comment to a cell

shift+space to highlight row, then ctrl+shift+'+'

Note, if you want those comments to be visible by default (more like comments in Word), then go to 

File > Options > Advanced > 
In the "Display" group, under "For cells with comments, show: click "Comments and Indicators"

Here are some other esoteric Excel tips (including formulas I like a lot). 

=average(CELL:RANGE)

=!sheet_name... [If you keep your sheet names short, you could do these references by hand, but the quickest way I've found to do them is to do the first one with point and click and then copy and edit it in other cells]