Anyone can sew. I've taught classes where students utter the words, "I can't sew", before they even try it. It takes a little practice and some know how, but once you have some basics down, you'll be machine sewing with professional results.
In my experience, threads make all the difference. I learned to sew when I was young, around 9 years old, making doll clothes, then my own clothes, later my son's clothes and quilts. I've used all kinds of threads like cheap polyester, rayons, metallics, viscose, nylon and cotton, and expensive polyester, cotton and silk, glitter, metallic, Charlotte's web thread, and neon light sensitive threads. If you're going to spend the money and time making expensive quilts, textiles, or clothing, why cheap out on the thread? The thread is what holds everything together and gives a finished look either in top stitching, decorative embroidery, embellishing and quilting, or just holding seams together. I started out using very cheap thread and the results were clear. My seams came apart after a few washes and the stitches didn't look neat. I had spent hours and hours, sometimes extending into years working on a quilt and in the end, I was extremely disappointed in it. I hate to admit that I have thrown away a couple quilts I've made, one being a twin bed size.
Another aspect to consider is your stitch quality. Make sure your stitching on the front and back are the perfect tension, length and quality. Do a practice swatch before sending your quilt through the machine. Adjust the tension knob to get the stitch to look the same on the top and bottom, either tighter or looser. One way to check if your thread is a good quality is to pull on it until it breaks. How easily does it break? Does it curl up at the break? Look on the inside of your bobbin case, is the thread breaking or shredding and leaving a lot of lint? I've thrown out spools of thread due to this problem. For years I sewed with Mettler silk finish cotton thread, but now I mainly sew with Superior thread's line; Masterpiece, King Tut, and Bottom Line threads. I also like YLI threads. The Mettler brand, Coats and Clark, and Gutterman brand thread shreds lint more than the
Superior Thread brand. If you've inherited fabric or threads from your Nanna or Mum, be cautious and check them out before you use them. Old threads can rot, fade, bleed or just break easily. If in doubt throw it out.
Your stitch quality may also be affected by the needle you use. Change your needle out with a new one every 4-6 hours of sewing. A poor needle can cause skipped stitches, broken needles and broken thread, and thread nests from the bobbin case. The needle makes thousands of passes through the hook and can become dull or a burr may develop. If you're very frugal, you could use emery or pumice to smooth out the burr, but I find this very time consuming and tedious, so I just opt for a brand new needle. Be sure to clean the lint away from the feed dogs, bobbin case and surrounding area with a dry swab every 4 hours of sewing. Use just a drop or two of machine oil on the racer and near the hook after you have swabbed the lint away. Bobbins should be wound with even tension and consistently around until filled. A big no no, is sewing over pins. It's the worst habit you can get into. It will destroy your machine and break needles and pins. These broken pieces can get lodged in the machine and move around into the works completely ruining your machine. I'm lecturing here, but this is a cardinal sin of any sewer that has this bad practice.
Buying fabric on sale is my mantra. If you're stash building, this is the way to go. Wait until fabric goes on sale and buy a yard or two. Stick with brands you know will be of good quality. I love to sew with Moda, Robert Kauffman and others. If you can see through the cloth, you may not want to use it for quilting. If it feels rough to the touch, wrinkles easily, or the print looks cheap or bleeds when it's blotted with a moistened swab, again probably not a good choice for a quilt or clothing.
I hope you will go away with confidence and a curiosity to learn more about your machine and perfecting your sewing. Happy sewing....;o)