Sarge ... I was once frustrated with it too.
You are not far from me, if you like I can either come by you, or you can come here and I can try to help you.
If this is not possible, I highly recommend Sally Collins books and video "Mastering Precision Piecing". This is what turned me around.
Tell us ... what methods and tools are you using already?
Do you use spray starch?? Trust me ... it helps IMMENSELY. Stiffer fabric doesn't want to twist as much when running through the machine.
Are you using a 1/4" guide? If so, are you adjusting your needle position? I've yet to find a 1/4" guide that really IS 1/4".
Are you using a walking foot?? Again ... this helps a lot. A nice even feed where the bottom fabric isn't tugging against the top fabric helps both pieces feed nice and straight.
Are you pinning ... and how?? Sally will teach you that you need to leave the fabric flat on the table when pinning, don't hold it up .. when holding it up you can/will distort the position of the fabric compared to when it is flat. Also, place every other pin horizontal to the fabric and the others perpendicular. This will help keep the position. And, use the longest pin possible and the tip of the pin should not encroach the 1/4" seam line.
Thread of course ... I know you mentioned you tried different threads, but you didn't mention which. I personally use Aurifil 50wt which is a 2 ply so is thinner than most 50wts, but not quite as thin as 60wt. I did recently purchase several cones of 60wt and I will try that as well.
Pressing. This process is more difficult for me to explain than to show, but this last step is just as important as the cutting and the sewing and if done poorly will give you a poor result.
Lastly if none of the suggestions are working for you ... are your blocks coming out slightly larger or slightly smaller? If larger ... no problem - trim them down. If smaller you can cut them 1/8" larger then trim them down if necessary.
The offer to meet is open though, I'm willing to help out.
Sue