Some tips for writing a song include using a rhyming dictionary, practicing free association and writing new lyrics for existing tracks. It may also be useful to find a songwriting partner with a different approach to melody and lyrics, according to soundonsound.
Free association is a useful technique for writing a song. It involves choosing a theme or topic for a song, then writing down every thought and feeling that comes to mind in relation to that theme, notes soundonsound.
For inspiration, it is a good idea to carry a notebook so that any ideas that come to mind can be immediately recorded for later.