I second the remark about the sun: good for first tires, but not for serious printing. You need a light source which can be controlled.
Also, in my experience cyanotype, which immediately seems to yield acceptable results, and has a reputation of being quick and easy, in my experience, if you want first-rate results, is considerably more difficult a process than, for instance, platinum.
For instance, the paper surface matters for the amount of density to be washed away. An, though nearly every paper gives an image, pre-acidifying is highly recommendable for most, but this influences contrast.
You might think about giving Mike Ware's new formula a try: while somewhat more difficult to mix up, this gives a considerably longer tonal scale and needs shorter exposures.