Here is a quick clean your Gmail inbox.
1. Sign in to Gmail > go to the big search bar at the top.
2. First, let's clear out the emails taking up the most space. Type Larger:10M in the search bar > hit enter or click the magnifying glass icon.
3. This will find emails taking up more than 10MB. Now select the mails you don't want > delete (trash can icon).
4. You can experiment with different file sizes, depending on how much you need to delete.
5. The obvious next step is to clear out emails from the long ago. You can use Before:YYYY/MM/DD to specify a cutoff date, or older_than:years if you want to search for mails that are one, two or more years old. For example, if you want mails that are older than one year, you can type older_than:1y > press enter to see the list, and then select mails > delete to make space.
6. You can use combinations of commands, so if, for example, you want to delete old mails with attachments that are more than 1MB in size, then type the following into search: has:attachment larger:1M older_than:1y > press enter, then see the list, and select items > delete mails.
7. In case you're starting to worry about remembering all these operators, then you will be happy to know that Google has you covered. Click on the downward pointing arrow at the right corner of the search bar, and you will see the advanced search, which lets you apply all these filters in a simple menu.