My tips for freeing up memory:
1. very important: check the "Other" files. Connect your device to iTunes via PC or Mac and look how huge the "Other" section is. This is mostly the cause for loss of space and can take up from a few 100MB up to 7-8 GB!!
The "Other" files are junk files, like temp data, install packages that accidentally doesn't got deleted and much more stuff. If "Others" is larger than 1.2 GB, get back to me, I tell you what to do. With IExplorer, there are some methods to handle that sh!t.
2. Save your vids or pics to your PC every two weeks and delete them from your device. Can free several hundreds of MB or even a few GB.
3. Apps like "Appshopper", "Tweetbot", Twitter", "Facebook", "Youtube" and much others are data collectors. You can check the original apps size and the amount of data they've collected under
"General" -> "Usage", then click on "show all apps"
and tap an app to see the original size and how much "documents and data" they stored. Uninstall apps like Appshopper, Twitter and others and re-install to get rid of the collected junk. DON'T TRY THAT with games, video players, graphic programs and music programs, cause this stuff are your savegames, pictures, vids, music, graphics or other saved stuff!
4. Clear cookies and cache of your browser under the Safari tab. Can free quite some space.
5. Clean up old mails and SMS stuff or back it up to PC and delete. Especially mails with attachments.
6. Make a list in your note app. If you have a game not played for at least 1 month, write the name into it and delete the app - it's unlikely that you'll ever play it again with the huge amount of releases every month. But this way you can keep track and always check which games aren't finished yet.
This methods might save you from having to delete your precious stuff. Hope that helped.
PS: If you're really harcore, reset your device to factory settings after a backup and install only the things you REALLY REALLY need or play. It seems hard, I know... humans are hunters and collectors. But it isn't as hard as it seems. Be a man, go through it.