Hey we have all been there.. At times I've had to just walk away from it for a while. the nine patch patterns are good to start with but the key is accuracy. When you have four, five, ten or whatever pieces of material and you're a smidge off every other time, they just won't go together.
I started putting a little piece of that stuff you use to line shelves or open jars between my long ruler and the fabric and then I don't shift it when I cut.I sometimes moved it just a hair and the end of a strip was wider than the beginning of a strip. What a pain to re line up and cut then.
I started out with a sampler quilt and you learn several different tricks in doing that. There are curves and appliqued blocks.They were all joined with sashing strips that made you square up each block to fit the sashing.It went together so well. But it was hand pieced blocks and machine pieced together. I am so much more accurate by hand but it takes forever.