Setting Column Width and Row Height in Excel Spreadsheets

It can be very fiddly to manually adjust the height and width of a cell in an Excel spreadsheet with the mouse, and pretty much impossible with the keyboard.
It is also difficult to know what the size of a cell should be if you have a lot of data with differing lengths of text and/or numbers.
A very handy menu can be found by pressing Alt + H for the Home ribbon and then O. This is the Cells Format menu and it includes options to set the column width and row height. It also has options to autofit column width and row height based on the longest data entry in a column/row.
To auto adjust the Row Height, press Alt + H, then O, then A.
To auto adjust the Column Width, press Alt + H, then O, then I.
Or, if they are a bit tricky to remember, then just commit Alt + H, then O to memory. There are other useful options in this menu (like going back to the default column width)