I noticed that this is your first tile, and that your border is messed up :)
I don't know if you read the tiling tutorial but I can tell you what your mistake was. You painted over the are of the tile that was given to you and expected it to blend like that on the quilt. Like the tutorial says, you should take the given area, put it on a new layer and move it to the top so you can't mess with it and paint all your stuff underneath it.

Good luck on your next tile!