I do not have a tutorial - but from the way I do things -
I start out with fabric that has been shrunk before I cut it . My method is to soak fabric in very hot water for at least three hours and then gently wash and dry it.
Once had a five inch square shrink over 1/ 2 inch in one direction when it was just washed in warm water. That is not typical, but fabric can shrink when it is steam pressed..
I do an accuracy test when I start - and generally check/ square-up as I go along.
Are my pieces cut the right size ? Are my HST unIts the size i want them to be? Is each unfinished block the expected Size? If not the expected size, then are they the same size?
it is easier - essential - to make sure things are " rIght " from the start than to try to fix a mess at the end.