You can also get a good file manager app,I use X-plore but there's a lot of other equally good ones for free.
Shift photos,videos,pics,songs,documents onto your ext card.That's essential housekeeping.
I take a lot of photos and use the flickr app a lot and have to empty both flickrcache and thumbnail file in the DCIM folder,within a week there can be over700mb of crap btwn them.