If you don't have a lot of data the cloud is probably not your best option because it uses Internet to access your stuff. Try backing up your photos to your computer regularly so they don't take up so much space? I run out of space all the time, but luckily I got my dad's old work phone today (he upgraded to a 6) and it has 4 times as much storage as my old phone :cloud9: maybe when you upgrade consider getting one with more storage.
Only keeping the music you actually listen to will help too! The rest can be stored on iCloud so you can still use it if you decide to but it won't take up storage on your phone
(Ps I had an iPhone 4 until today so you're not alone!)