I have too many ideas and I can't settle on which novel to write first ... any advice?

Well, u could try to combine a few of your ideas. However, if they are so completely unrelated that doing so would be impossible, u could do what I did. Start with your favourite. And when u get a writers block, start another. At the moment I am writing over 10 stories, and that's working pretty good for me!

Just write them all out how u think they should go, any part, it can be any part: start, middle, end, anything inbetween. If there's any u like (or in my case all of my roughly 14-15 idea's) then just continue them all on as u get ideas. Another way to do it is play all the idea's out in your head, place yourself in the main character's shoes, be them, it's surprisingly fun, as u meet new characters along the way. It's a way to test your imagination, and if u get ideas about how certain characters, write them down their name, age, bio, status in book.