Those black lines that you have on your borders really make it hard for other artists to blend into your tile.
Also, keep working to improve your blending skills from the tiles you've been given. If you're using photoshop, you can use the eyedropper tool to pick an exact color out of the borders you've been given. This helps tremendously when trying to color match with the border.

Keep tilin'! I can't wait to see your future tiles :)

-Fydo