Prior to starting the process you should make sure that your bearings are adjusted, belts are properly adjusted and in good condition, and that your optics are not loose. Pick a material that shows contrast well and is easy to score. You should run a base line test with your offsets enabled, disabled and with bi directional engrave disabled so that you can verify the initial issue and health of the machine mechanically. If the engrave with Bi-Directional off yields poor results, you have some other issue (possibly a tube firing issue) to consider.