I am getting a Goodman gmvc 950905dx installed in my home .I have read a lot about Goodman and other furnaces and other brands .Seem to me all brands have issues and I feel quite confident in what I am getting .What are some of the small PMs to do for an efficient running of my furnace?

Most important is to keep a clean filter for the unit. I suggest checking it once a month, and change as necessary. Other than that, new units are pretty much maintenance free. Draft inducer, and main blower motors are sealed, so there is no oiling to be done, so pretty much all you can do is keep the unit clean, and hope for years of trouble free operation.