It really is a case of practice. I did a class but don't believe it was any help. Best advice I got was stop worrying and go for it. There is always going to be someone who'll be better at it but so what. We are much harder on ourselves than anyone else is. I've never had anyone else mention my mistakes in all the quilts I've given.
Just go for it and don't get hung up on the results to start with - don't compare yours to anyone elses. BTW I'm still not very good at it but have a go every now and then.