I'm currently writing in 1st person (and want to continue to do so), and have an incredibly clear characterization in mind for the narrator's best friend (too much of a wildcard to write intimately), but I feel that in doing so I'm neglecting the MC as it were, and that she serves no other purpose than to describe the people and goings on around her. Her observations are very emotionally astute, and I know that sometimes a deep empathy with others can breed introversion, but I can't help but feel that any insertion of 'personality' breaks up the flow of the writing and feels forced, like I'm putting the brakes on the whole thing in order to shout 'and she's a big fan of cycling and enjoys chocolate chip cookies!'. I want the general feeling of the book to be one human being observing many others, and I don't get the same feeling from writing in 3rd person. Then again, I feel as though perhaps I'm simply inside her head too much, and can't see the personality that develops from hearing her internal monologue? Does anyone else feel a little guilty for sidelining their main character and falling in love with another?
Feeling guilty is pointless. If you are aware you are shortchanging your protag's development, fix it.
POV characters rarely described themselves, and it's not uncommon for the MC to be a bit bland compared to those around them. look at Stephanie Plum versus Lula or Grandma Mazur, Jerry versus George or Kramer. the POV character's personality will become known through her choices, her reactions to events, her dialogue with other characters. does her friend's wackiness exasperate or excite her? does she cycle to counteract her love of cookies, or just because it's fun? even if she's describing the other people in her life for the reader, her actions will show the reader who she is.
Sometimes they say you need to find who the person is who is telling the story while in the idea phase.
Well, Sherlock Holmes is in first person from Watson's POV and yet the MC is Holmes, right? It can work. Are your sure the supposed "side" character isn't the real MC?
Lou W would you read a reference book if I recommended one? It would take a lot of work. However if your prove to me you bought it I can share notes if permitted by the rules, which I don't know if doing this by email is allowed. However, think of the machinations of the character based on, the antagonist first and how he affects the MC.