Fig. 1 Resizing a column by dragging. You can also resize more precisely by holding the ALT key down while you drag. You'll also see the column width change on the horizontal ruler.
Fig. 2 Resizing a row by dragging. To resize more precisely than dragging alone allows, hold the ALT key down while you drag. As you do this, you can also see the row height change on the vertical ruler.
If you want a different width or height for a column or row, rest the pointer over the right edge of the column or the bottom edge of the row until your pointer changes to a double-backed arrow, as shown in the illustrations. Then just click and drag to resize.
Caution Avoid selecting individual cells when you use this method to resize columns. When cells are selected within a column you're resizing, only the selection will change.