It is crucial to have accurate and clear presentation of your analysis.
You should use font and font size that will be readable and be presentable. In a file, I prefer Font "Verdana", however, "Arial" and "Times new roman" are very good too. I use Font style "Regular" and will bold areas that I want to draw more attention to, such as column titles or summary.
Font size "10" in my opinion is a good choice for the excel file to view on a computer screen or to print on a regular paper size. However, if you are doing a presentation and need to project the spreadsheet on projector screen, you may want to adjust the size accordingly.
When a cell or a range of cells are highlighted for which you would like to change font setting, go to the file toolbar and follow this pass by clicking on Format / cell / format and make the selection.
Page setup for print:
Always format your analysis for the print. This is a must. Go to File / Page Set up and make your selections. Preview before you print.
Page setup for view on the screen:
If, in order to re-view your analysis, you need to scroll horizonal or vertical, you will need to freeze your column and row heading for easier viewing. Click on the cell right below intersection of columns and rows heading and then go to Windows / Freeze panes on the file toolbar.