When it comes to writing a song, or in any craft for that matter, some of the most interesting results come from when one breaks the rules. The one huge caveat that many songwriters forget when doing this is that you need to know and understand the rules before you can break them. You can break a specific rule to get some effect, but a great artist does for an artistic reason. They know the parts of a song's structure and the purpose of each. The chorus, verse, bridge, solo, intro, development, outro, etc. all play a certain role in telling the story and taking the listener on that musical journey. For example the verse may set up a general mood, the pre-chorus may escalate that smoothly into a more intense and direct chorus, the bridge gives you a break from the repetition so that when you come into the last chorus it feels fresh again. 

To get a better handle on song structure take several favorite songs and listen only for structure. You can do this for any specific element like melody, dynamics, arrangement, production, etc. You will inevitably start to hear patterns. "Rules" for lack of a better term such as rhythm, melody, structure, tension and resolution serve to give a foundation to ground the song. You can break some rules and balance and ground that out by enforcing others. If you break all rules it sounds like anarchy or noise. If you break none of them, that can be very formulaic, predictable and boring. 

Many indie artists often think of "hook" as a negative term. Like something only some pop tart top 40 formulaic songwriter for hire would use. In fact, Mozart, Beethoven, Dizzy, Miles, to Stevie Wonder, to Frank Zappa and the Beatles all use memorable melodic hooks. If they didn't you would never remember or want to remember their songs. The hook is the reason the vocal catches your ear in the first place. The part you wind up singing in the car on the way home from the concert. It is something the ear can grab on to, that moves song from one place to another, and tells the story. Not just notes in the key, or runs up and down scales. Even jazz improvisationalists such as John Coltrane start with a melodic motive then develop into a journey to very out territory from there then take it back home. This is why jazz and fusion always seem to remind me of a great roller coaster ride. 

All music and life for that matter is made up of cycles that progress between various states of tension and resolution. Science, nature, breathing, and music are just an expression of already existing principles of life and the universe. The rules aren't made up by the musical status quo they were discovered based on how nature and human nature work. If you play a Beethoven string quartet for your pet it will calm them down, if you play Stravinsky or Bartok they will probably become rambunctious or uneasy. Everyone has seen those YouTube videos of someone's pet bird enjoying dancing to some bouncy tune. This shows how certain dissonances of rhythms and harmonies simply express tensions and resolutions in the world. You must keep this in mind and use that to express the story of the lyric. As well as use it to simply progress the flow from one part to the next, one note to the next, one beat to the next, one progression cycle to the next. 

The bottom line is that you need to be relatable and repetitive enough to draw the listener in and not alienate them but have enough novelty thrown in before they get bored. Like anything, it's about playing with tension and resolution and balance.