Set your Spreadsheet Workspace
An Excel workspace (sometimes known as an arranged workspace) is really just a special file that keeps a record of all the workbooks open at the time you save the workspace, as well as all the workbooks' screen attributes - things like window sizes and arrangement, screen magnification, and any other display settings in use at the time. Workspaces are real timesavers because they enable you to immediately resume work the next day on whatever workbooks you had open the day before. All you have to do is open the workspace file, and Excel does all the heavy lifting: opening the individual workbooks and arranging their windows and setting up the screen attributes so they're in the same condition you left them in.
When you're involved with a particularly complex spreadsheet project that requires you to work with the same workbook files over the course of several work sessions, you can save even more time by having Excel automatically open the workspace file when you launch the program. That way, you have all the spreadsheets open and arranged so that you're ready to go the moment you start working with Excel.