Manage your time wisely. If you have to, pencil in a songwriting block into your daily routine. Life's not that set in stone, however, and you will most likely find it impossible to maintain a strict songwriting block every single day. Be flexible. Songwriting isn't just something you can do sitting there with a pen and pencil or a guitar. You can "write" songs anywhere and anytime. For example, if you find yourself out all day at school, at work, hanging out with friends, etc., think of melodies and lyrics at breaks in conversation or when you're standing on line. At the same time, be aware of the world around you. That billboard you pass on the highway may be inspiration for a lyric, just as the sound of your alarm clock may set off a melody in your head. The only way to write a song every day is to be conscious. You will find it incredibly hard to write from a blank slate.
Force yourself to write even if you seem to have no inspiration. Carol King and her husband Gerry Goffin were staff songwriters at the Brill Building in New York City in the 1970s, where they were expected to write new songs on a daily basis. Work like a professional songwriter. Hum whatever melody you can think of. Write lyrics about the guy who cut you off on your way home.
Organize your music and lyrics. If you find yourself stuck, perhaps you can finish a song that was never finished. It will be much easier to fill in melodies and lyrics to songs you're working on if you maintain a notebook or database of everything you've got. Arrange your lyrics over time into categories, such as "breakup songs" or "political songs." Arrange parts of songs in the same way, into categories like "verses" or "riffs." Organizing will help you write every day, and it will also help you to keep track of all the new songs you have written over time. Label and record all your songs in a uniform fashion. Put them all in the same folder in your computer or on labeled CDs.