Second thing I do is get my maps and props ready. For modules I import the pictures into Photoshop and blow them up to scale and print them off and piece them together on poster-board. This makes your maps look really good and makes prep easy. If you don't have any module maps you can take a ruler and grid off 1 inch squares on poster board then draw your maps that way. Having your maps ready ahead of time really speeds things up. I used to draw them but it seemed like half our time was spent with me drawing and everyone else goofing around then I had to wrestle their attention back after I was done. Its always a good Idea to bring extra pre-gridded posterboard in-case you need to improvise a scene. I have a couple sets of the pre-made dungeon tiles these come in very handy for these situations. You can find those over at amazon pretty cheap.
Third go through your minis and separate out the ones you will need into zip-lock bags for each room or if your module has specific themes like orcs or demons or whatever just grab all of that type of mini and put them in a baggie. Doing this will save you tons of time usually spent sifting through minis setting up rooms.
Lastly go through the module again in detail and check out each of the monsters abilities and think about how you plan to use the monsters. A well planned attack can turn a easy encounter into a challenging one and vice versa. I've had problems when I didn't think through my tactics enough and the monster that's supposed to be the focus of the encounter gets trapped by terrain or is bested by inventive players very easily. This cant be helped sometimes but a little forethought goes a long way in these situations. Here's a few pics of me prepping the maps for our game this weekend.