Start with a medium sized pot with a lid - Le Creuset makes a nice 8.5 round casserole pot but you don't have to get fancy (any pot will do). Begin to heat your pot and thereafter (about 4-5 minutes later) add the finely diced onions and garlic (along with a bit of salt and pepper). Saute the onions and garlic until the mixture becomes translucent and, thereafter, add the crushed tomatoes and stir well. Bring the mixture to a boil and then set your heat to simmer. Next, add the sugar, dried oregano, pepper, and salt to your pot and mix well. Let the mixture simmer for 35-45 minutes without the lid (you can keep the lid on but your sauce will become a bit thicker). You'll want to mix the sauce every 15 minutes or so. Some folks let tomato sauce simmer "for hours", but I haven't found that a longer cooking period increases flavor (what it does do is turn tomato sauce into thick "gravy", which isn't very appealing in my book).Once the sauce has finished cooking transfer the contents of the pot to a food mill; note, the food mill should sit on a large bowl to catch the processed tomato sauce (I like to do this in the sink so I don't make a mess).A food mill is a great, inexpensive, tool and it yields a perfect consistency for tomato sauce (and also opens up the flavor of all the ingredients).