My macbook storage

Hello,

I have a Macbook Air 13 Inch, but the storage stays full. I cannot update my macbook anymore, because of lack of storage. I have deleted almost everything from my computer, but the box 'other' keeps the same, it's currently on 100 GB and my movies and documents and such are currently at a total of 20 GB. Can somebody help me out, I tried deleting some cache and programs such as chrome and Word that take alot of space but it does not help.