QUESTIONS I HAVE ABOUT WRITING MUSIC

I'm working on some projects with musical elements and I have some questions
  1. Which are the best notes
    So far I feel like G is probably the best, but there are some others that I think are pretty good, too
  2. What's a good order to put them in, generally
    Priority for me would be the song being best, so keep that in mind
  3. How long should you play one note before going on to the next one
    Please be specific in terms of each note and how long to play it so I know
  4. What do you play the notes on
    And where do I get that
  5. Where on an instrument are the bad notes
    So I don't play them
  6. How many notes should I use
    In total, for the song
  7. What are the lyrics