The first method often used and not really the best method, but it works, is to share your documents with another Google account. You will need to go in and change ownership of the documents and this could be time consuming if you have a lot of documents.
Luckily Google has provided a much easier method for you to save your data. The preferred method is to use Google Takeout. If you go to Google Takeout while you are logged in you will automatically be taken to where you need to be to archive your data. Select the products you want to archive. In the image below I selected Drive.
After you have selected your Google product to archive, click on the Create Archive button and the archive process will start. Once you start the process you do not need to remain on the page.
It will archive in the background and you will receive an email when complete.
You can now download your data to an external drive. In my situation all of the files were downloaded as Word, Excel and PowerPoint files. Note that the archive needs to be saved or it will automatically be deleted and you will need to run the archive process again.
If you do not receive your email in a timely fashion you can go back to Google Takeout and select My Archives to access your file for download.
Remember to never save your files to a public computer. You should save these files to an external storage so you can take it with you.