I could start by explaining the importance of doing regular backups. However, I believe that almost everybody knows how important it is to store important data, and how crucial it is to back it up from time to time. There are a few ways you can store it:

• You can store it online. By this I not only mean your email account, but also services of companies that allow you to store your data on their disks. Often a certain fee might be associated with it, so it is up to you whether you want to pay for this kind of services.
• You can store it on external hard drives. Those usually have a large capacity and thus make it the cheapest and the most effective way to store data. I would recommend them to most people, as there are very few drawbacks.
• You can also have additional hard drives inside your PC. Just by installing additional drive in your PC, you will have more space to store your precious data. Take into account that your energy bill might grow because of it, as you will have two hard drives constantly operational.
• CDs and DVDs. Although those do not contain that much free space, their price is not that high, and you can fully rely on them.
• Store data on another PC. If you have a home network, then you can simply copy some files to another PC by using your LAN connection. This is a quite fast way to backup data, but it requires an operational network.

I am not going to recommend a specific method for every type of user, but try to remember that it is important to back up your data on a regular basis.