Just get in the zone and look at the overall area, the closer you stare at the needle the easier it is to OVERSTEER, just like driving. Focus on a spot in front of the needle where you feed the fabric in and let the fabric SLIDE under your fingers, and the presser foot do the work of pulling in the fabric. Try to not let the fabric pull your hands towards the back of the machine, you will then be in control and able to guide the fabric straight with very minute adjustments. Been sewing over 60 years and it just gets to be second nature.