Bad habits or a lack of experience with certain Office features can lead to a lot of confusion and time-consuming rework. This ebook offers some easy ways to prevent those headaches by avoiding common mistakes in Word, Excel, and Outlook.

From the ebook:

Mastering Excel takes some experience and patience, but it’s easy to make mistakes even if you’ve been using it for a long time. Sometimes, choices seem like a brilliant idea—until they’re not, and the resulting problems are hard to troubleshoot. In this article, I share 10 ways to avoid actions that seem good… at the time.

Here are 10 things you should never do in Excel.

Rely on multiple links
Links between two workbooks are common and useful. But multiple links where values in workbook1 depend on values in workbook2, which links to workbook3, and so on, are hard to manage and unstable. Users forget to close files, and sometimes they even move them. If you’re the only person working with those linked workbooks, you might not run into trouble, but if other users are reviewing and modifying them, you’re asking for trouble. If you truly need that much linking, you might consider a new design.

Destroy data
Users sometimes use the same spreadsheet for new data by overwriting the existing data. For example, you might enter this week’s sales figures over last week’s—destroying last week’s data. In the short run, this process seems innocent enough, but if the data’s important enough to record, it’s probably important enough to keep, at least for a while. Instead of overwriting existing data, use a template to enter new data and name the sheet or file appropriately. Keep your data intact so you can refer to and evaluate it later, beyond its seemingly short shelf life.

Rely on default settings
Excel defaults might be adequate for some or even most users, but if you find yourself resetting things every time you start a new workbook file, stop. Instead, open a blank workbook, change those settings, and save the file as a template. Then, base new workbook files on the template instead of Excel’s built-in template. Or alter the default workbook.