Store more apps on iPhone 5c 16gb
Solution 1:
About the only option is to have all the apps you want on iTunes and load them onto your iPhone as desired. Of course you can't have them all at the same time because of your memory limitations but you could change sets for vacation or work for instance.
Or you can buy an iPhone with more memory.
Those are the only options Apple leaves you.
Happy Day!
Solution 2:
iOS does not have the concept of a file system for users to access in the first place. Even if you use a dock to USB / camera card adapter, the OS will read files from th storage and ingest them into the photo app.
Short of a jailbreak, you will not be able to extend the storage in an analogous manner to Android, OS X, Windows of other computer-like OS.