I know many, if not most, will not agree with me, BUT since you are a beginner, it is consistency that counts the most. You are probably using patterns and designs that are not too complex. Pick a seam allowance, for example width of the sewing foot on tour machine, and stick with it. If all your seams are consistent, your pieces should fit just fine. As you get more experienced, you will get to the elusive 1/4" seam. Up until recently, I had a machine on which 1/4" seam was impossible due to the position of the feed dogs, and I still made some awesome quilts including Bargellos. Good luck!