Understanding contrast and value is very important in making blends. Sometimes you will want a dark to light blend that goes almost to white. Sometimes, you will want subtle, rich color blends that go from light to dark without losing intensity. These canes from my Picture Cane Tutorial use the more subtle blends like the Leaf blend and Ocean blue blend.
To make an Ocean blue blend (the block on the left), just make a basic blend from Ultramarine and Turquoise.
Here you can see the difference in value.
Leaf green The dark green is 2parts black and 5 parts green. The light green is Wasabi.