Once a small part gets lost in grass or on floors, you can waste a lot of time looking for it. To find it quickly, put a nylon stocking over the end of your shop vacuum hose and fasten it with a rubber binder. Turn on the vac and play it over the area where it might have gone. If the part is there the vac will suck it up and hold it on the nylon so you can just pick it off.
When using latex be sure that the temperature is above 50 degrees F. It is difficult for latex to form a film at lower temperatures. With solvent-borne paint, be sure the temperature is at least 5 degrees above the dew point. If it isn’t, water may condense on the surface as it cools while the solvent evaporates, causing an uneven blushing effect.