You my only friends because no one wanted to be your friends and my mom made me jk tell them that you love them and that your very thankful for them. Just go from the heart and you can write the song.
it depends on the friend your talking about and take what he or she likes their personality and what you think of them you can also listen to other songs and take bits and pieces and put it together i do it all the time sometimes i listen to a song and listen to the melody and i take the background music but you have to get their permission sometimes or that's copyrighting.Hope this helps you. chat me if you need more info. :)
