First of all take yourself and your camera to an autumn woodland - or anywhere with some colourful scenery.....
.....a bit more contrast might help.
.....and more colour saturation.
That's quite nice but for some reason the colours don't look very autumnal. Hang on, we can change the colour temperature, warm it up, more reds and browns....
I'd probably crop the image a bit. Like this.
No, probably not a good idea!
But I could have made a fortune designing album covers for Jimi Hendrix!