When I first started quilting I picked one fabric that I loved (I call that my main fabric, feature fabric, or theme fabric), and then choose a background fabric as the 'canvas'. I brought my my main fabric with me to the fabric store so I could pick other fabrics that use either the same color(s) or coordinate with that fabric. I always used the background fabric in each block, and I often used the main fabric in each block.
Now I often have a background fabric or a background color, and then work with color families.
|Clockwise from left to right: dark blues, medium blues, light blues, white (background fabric which will be used in all the blocks)|
|This line of fabric was created so that they all match. Not much value difference in these, the top left is definitely a dark color, but much of the rest is medium color values.|
|The blue provides the dark value, the yellow is a medium tone, and the white is the light. In this block the yellow is used as the background fabric and the white is the light.|
|In this block the white is the background, the green is the dark fabric, and the yellow is the light .|
|In these blocks the basket part of the block is dark and the flower part of the block is medium or light.|
If you don't want to 'mess up' or 'waste fabric' then take a deep breath and realize that there are no mistakes--only unwanted results. If you learned something from the block you just made then it was a success and worth the time spent.
Here's something to make you feel better: I just tossed one completed block into the garbage because I measured wrong and it turned out too small!
Here's a link with a tutorial about color theory for quilters:
Color Basics for Quilters
Here's a video on making your own color wheel with your own colors:
A video describing color value ("You know what you love, you know what colors make you happy, go with those colors"):
Choosing a theme fabric: