I too completed my first rug a couple of weeks ago. I also watched the YouTube video; it was really helpful. I think the key is to make sure you have the rug completely flat at all times as you sew - I used an extension table and then had plastic storage boxes and books all around that so when the rug got bigger, it all stayed completely flat. I also think it is important to not only to press every 2-3 rows; but when you press, make sure it cools completely flat before taking it back to sew. I have had no problem. I hope this helps.
https://www.youtube.com/watch?v=Y8xblarkuBg