It was today after more messing about that I realised anyone could write a half decent catchy song; heck I've been playing since December and I have the ability to write some really nice sounding stuff. All you need is a simple melody to get you started.
There's a particular favourite chord progression I've been following lately and it is made up of just three simple chords (A, B, G, A). Like the song 'Chasing Cars' by Snow Patrol, its brilliance lies in its simplicity; well that and the overall brilliant lyrics! The two go hand in hand.
So to start simple is always a good idea, riff writing isn't hard, it's the rest of the arrangement that takes time. I often start with the bass notes to make the initial melody and have it loop over and over while I find high notes often on the bottom strings (G, B, e). I create a repeating plucked riff to follow the bass melody, often made up of the same notes as the bass-line, it's never complicated, it's just something to further accent the bass riff (use Chasing Cars for a reference point).
It's at this point where things start to get interesting. You basically have the makings of a really cool riff going on. I tend to mess around with guitar distortion or maybe a high end solo piece, once again nothing complicated, 'cause well I'm not that good! But anything you can play, as long as it follows the 'root notes' will add something to the riff.
I have had a lot of fun just messing about with ideas and adding extra bits to the melody. It is really great practise too, it really gets you using the whole the guitar too. So for me; it's a really brilliant way to improve your guitar work if like me you've not been playing for long.