Set your old texts to automatically delete
There's no good reason to save that "hey what's up" message for eternity. But instead of deleting those old garbage texts one by one, simply go to Settings > Messages > Keep Messages. Decide how long you want to keep them around, and your phone deletes the oldies in one fell swoop.
If you use Safari a lot, it's likely storing a ton of unnecessary web history and data to keep you browser ever-so-slightly faster. Clear that mess in Settings > Safari > Clear History and Website Data.
Purge your extraneous Instagram photos
And tell Instagram to stop saving them
This preventative measure ensures Instagram will stop saving photos in a separate album in your Photos app. Open the Instagram app > your profile > Options > unselect "Save Original Photos."