Purpledog hit on something that really makes a difference for me--squaring up the units in a block before I put them together. When I rush I am always tempted to skip this--but then remember some quilts I did (3) which I call my "no points" series cause I ended up with blocks all over the place size-wise and too often the points "went missing". So now I force myself to slow down and not skip this all important step.
I also got an Accuquilt Go as my cutting would get sloppy before I'd get a quilt all cut out (and I usually like to cut the entire quilt at one sitting so I know immediately if I have a fabric shortage). that has helped a lot too. I also check andn adjust my 1/4" seam with each project--thank goodness for needle positioner on my machine.
Can't say mine are always perfect, but by focusing more on precision and taking my time they are getting better.