Here are a few tricks I've learned:
Use much finer screws, yours look like 1/4-20 which make it hard to make adjustments on the order of microns.
Use a laser pointer reflected vertical some distance to help line up the two reflections.
Get rid of your air bubble to keep the background dark.
You will likely have tightly spaced fringes at first that are hard to see so use a magnifier to look for the fringes in a small area, open up the fringes then go to a larger lens.
Use a thin water layer; overfill it then see how much water you can remove before leveling takes too long.
I use a F4T5 BL flourescent blacklight bulb used in bug zappers.