Google Drive shows you your storage usage in the top left when you click on "Storage" - you'll see right away what's taking up the most space 📊 Most people are surprised that videos and high-resolution photos are the culprits. You can also filter the overview by file type or folder in the settings under "Manage storage" to see exactly what's taking up space where.
My tip: Start with the big files - look through your videos and old photo series, that's usually where you can delete the most without losing anything important. Before you delete anything, move it to a separate "to delete" folder and leave it there for a week. That way you'll notice if you actually need it after all 😅 For really important stuff: make a local backup on a USB stick or external hard drive first, then you can sleep better.
If you really need a lot of storage, a cheap Google One plan is worth it - 100 GB doesn't cost much and then you've got breathing room again. But first you should definitely clean up and check if you really need everything 💪