Good start XJazz!
There are a ton of things to take into consideration when making seamless tiles. Most of them can't be automated.
Like the dry leaves and the green patch near the bottom in the final image will cause major repetition on a terrain. Those would have to be edited out manually.
For those with photoshop, the offset filter and the healing brush work wonders.
I didn't work on this more than 5 minutes so don't laugh. But it shows what I mean...
Leaves present in texture...
Leaves removed from texture...