My work in progress, Jewel of the Sea, has romance, coming of age, friendship but one of the strongest themes is metamorphosis.
I use the Simple Note app for jotting down ideas as I always have my mobile phone with me. I do have physical notebooks but tend to use them more for development.
I always feel that a well developed antagonist can be both good and bad. Most people have a reason for their actions. It depends of the perspective.
I have loads of boards. I have boards for character development, cover designs, mood boards, etc. I save useful articles for tips on writing, blogging, vlogs, etc. I’ve got boards with useful crafts, recipes and hair tutorials. I have used it for my sons homework, party planning and decorating rooms.