What kind of computer do you have?
Cloud services like Google Drive is a good idea. I'm personally paranoid about my data so I have an extra hard drive synced with Google Drive so I have a backup just to be safe.
Other tips:
1. Defragment your computer. You can find the defragmentation tool by either searching for it or finding it on the Control Panel. If you're having trouble with that, third-party freeware like
Defraggler.
2.
CCleaner can also help. There is a lot of useless temporary files that your computer tends to hoard every now and then.
3. Buy some external hard drives. 1 TB can go for less than $50 on Amazon.