If you have downloaded stuff from the internet, that stuff goes to your Downloads folder. Try deleting any files in the downloads folder that you no longer need (such as .zip installer files).
Also, in case you don't already know, after you delete files, the files are still on your hard drive until you empty your Trash.
If you already know how to do all that, here's another method:
• Select several files (up to 2 GB total)
• Compress them into one "zipped file" (right-click/control-click & choose "Compress
x items"
• Email the zipped file to yourself for free, using
WeTransfer (just click "Skip" when you visit wetransfer.com, because you will be greeted with an offer trying to sell you WeTransfer Plus).
• Be sure to use your email address as the "sender" & "recipient".
• The files will be available for you to download (using a link which will be emailed to you). You can delete the files after you receive the email with a link to download your files. However, this is a temporary fix, because you will have to download the files before WeTransfer deletes them.
After you free up some space, get
GrandPerspective for Mac , which is a free Mac app for seeing where your big files are.
Also, a cheap/easy solution will be to get a cheap USB thumb/flash drive and copy important files onto it, then delete them from your MacBook. You can get about 32 GB for about $10 if you search
www.slickdeals.net or
www.dealnews.com