First things first.
1. START TO PLAY AN INSTRUMENT
Ideally learn to play a basic melodic instrument; guitar, ukulele or piano.
Playing an instrument will make you an independent song-writer and singer. Believe me- depending always on a someone else to play the music for you is not ideal. The instrument will take your song-writing to another level because playing an instrument, at least in my experience, helps you to connect with music better. Even with the easiest chords (ukulele for example) you are able to play a bunch of songs. And with couple of chords you are able to write a bunch of songs.
With 4 chords
G C Am F,
you can already play Price Tag (Jessie J), I am Yours (Jason Mraz) and many others.
Some of the most popular songs use only 4 chords for the whole song (Pumped up Kicks, Soul Sister..).
Once you start playing an instrument you can start your song writing process.
3. DECIDE YOUR STRATEGY
If we simplify it: Song has 2 main aspects. These are MUSIC and LYRICS.
Music- the chord progression (sequence of chords on guitar, ukulele, piano..)
And the Lyrics- text, verbal melodic expression.
You can choose what to write first. MUSIC or LYRICS.
It is easier to create a MELODY within the music you are able to play (in case you are a beginner with an instrument) rather than create a melody and then search what chords you need. In case you are a beginner you could be limited with number of chords that you have learned to play so far.
I personally usually write the music first. If you write lyrics first, wait with the melody for the music.
Start jamming with some chords and see what sounds good and makes you feel something. Once you have a CHORD PROGRESSION, start coming up with the lyrics and melody of the lyrics (or melody for your lyrics).
Understand that music and lyrics are tightly connected for couple reasons. Remember, that music gives the mood of the song- (MINOR CHORDS chords are rather melancholic and MAJOR CHORDS rather joyful).
4. START JAMMING
Play some chords with your instrument of choice and find a combination of chords that you like- that fits the mood of a song you are going for.
I usually find the combination of chords I like, and then I play these “on repeat” and I record myself singing on top of it.
In this way I come up with both lyrics and melody.
These advice and knowledge are based on my experience. Hopefully this can guide or inspire others in order to write songs.
I hope you learned something new and I wish you all good luck wth your song-writing procces .