Which method are you making?
The first thing I would do is measure your seams.
You need to be using a 1/4" seam.
Are all of your 4 little blocks the same size?
That will also throw off your pinwheel block if you had different sizes.
Press carefully when you make or cut the 1/2 square triangle blocks. If all the sizes are the same then carefully pin your center seams and using that 1/4" seam try to sew them.
Another thing if you are trimming your 1/2" square triangle blocks make sure you are taking a little off each side, not all off one or two sides.
Keep trying. Maybe watch the video again.
HTH
The top two don't look so bad. Check that seam on the bottom two.