Worksheets can get very big, very fast. Often you want to still print an entire worksheet in a single sheet of paper. Excel makes this easy to do by using scaling.
The easiest way to scale what you print is to display the Page Layout tab of the ribbon. You want to pay particular attention to the Scale to Fit group; it contains controls that cause your output to be scaled. You normally specify a height and width (in pages) and Excel takes care of calculating the scale necessary to fit the data into that number of pages.
One of the tricks I often use is to set the Scale to Fit settings to 1 page wide by 99 pages tall. In this way, I am sure the output will fit on one page across. Since my output isn’t over 99 pages in length, no shrinking is done on this dimension. I end up with output that is 1 page wide by how ever many pages long Excel needs to print.