Filtering is important. Find out to the micron rating of your standard diesel fuel filter and filter below that.
My veggie fuel filter from GreaseCar (Fleetguard FF-5156) filters to 15 micron. I filter my oil to 10 micron using two bags - one in the other. Next season I'm going to 1 micron. You can never be too careful I figure.
I found gravity feed to be very easy and simple for the amount of fuel I process (1000-1500 Litres per year).
I get my filters from FilterBag.com.
Check out the video, it explains things better than I can with a keyboard.