Nothing will put me in a worst mood then when it seems like my sewing machine is acting up and I can't get my stitches to look right. My instinct is to naturally blame the sewing machine when, nine times out of ten, it's user error and it's really my fault. When going through your sewing machine troubleshooting, one thing you should consider is your presser foot tension, also commonly known as the presser foot pressure, which could be a dial, screw, or knob on your sewing machine. Not all machines have this as an accessible adjuster but, if you do have it, you should familiarize yourself with it. The presser foot tension can affect your machine's performance. This video informs you of what the presser foot tension is and when you should be adjusting it to make you an expert at using your sewing machine.
Presser Foot Pressure – Tension