Try doodling with pencil on paper or just with your finger on the table. Believe it or not, your brain will retain the muscle memory and it will be easier once you try thread on fabric. From your description it sounds like you have not found the sweet spot when the speed of the machine and the speed at which you move the fabric go in synch. When the machine is too slow and you move the fabric too fast, you tend to get jagged edges. When the machine is too fast and the fabric moves too slowly, you tend to get angry tiny little stitches. Try speeding the machine up a little.
How is your table set up? I noticed that my machine was too high and when I quilted, I developed "wings" (aka shoulders by the ears) which made smooth movement of the sandwich tough.
Are you wearing quilting gloves to help you move the sandwich easier? I use "machingers" - they are very thin and non-obtrusive.
Are you using a sheet of vinyl on the machine table? It helps cut down the static electricity and MANOHMAN does it EVER make a difference in fabric movement.
Those are all the tips I got. Don't give up. It will get better.