PMF Gooru's I am your student

OK all you PMF Gooru's . I've done 3 different parts of my TTT's interior wall canvas work. I have a question. .... How are you guys getting those Nice /perfect seam/overlap lines ? And not having any stray stinger threads , from cut canvas. I'm using HF canvas. I removed all the seams with a seam ripper and ironed the canvas. But even if I had bought more expensive canvas, I'm sure , I would still have this problem. I'm not so concern about the interior. But when I do the exterior. I sure would like for it to look straighter/better. Gooru's teach me the way 
