I also think blending is about having the right brushes. I bought a couple brushes from mac and I just put the eyeshadows on using those brushes and everyone says oh wow your blending is sooo good.
But, it's also about the order in which you place your eyeshadows on your eye.
I do my regular everyday makeup scheme regardless of color in this order.
Lid- Color 1
Crease to Beneath Brow- Color 2
Brow- Color 3
Serious Crease- Color 4
I know that I did no intentional blending. It was the brush.
But other times when like doing a horizontal colorscheme I have had to blend those colors together.