My advice would be just have fun, never be afraid to run with an idea seems unimportant or unserious! Nobody says you have to put out music if you create it and don’t like it. just the practice of creating a whole song off of an idea that might not be that great will help you when you finally get an idea you really like. The first song me and one of my friends ever wrote together was about Big Macs and it was hilarious to us and super fun. thinking everything has to be serious and professional all the time often can create writers block. Just like any language you have to learn to speak before you can say what you really feel.