Until I met someone who actually wrote EVERY day, I didn't think they existed. Yikes. Talk about hard work. I write song titles down as soon as they pop up. If and when they do. During the day or night or whenever. It's good to scribble down dream-songs as soon as I wake up. I've gotten some good ones that way. I also scribble down lines or thoughts in a book I carry around in my pack, and stack them on top of the monitor for later. When I'm writing for musical theatre, usually all it takes to get the song out is the character's subtext, and who they are, and where in the show it's going to go. The director says something like, "We need a song here that says...", and that does it for me. The story of the song is the most important element to me. Everybody's different. Find the way that works best for you.