Smoking areas:
CityWalk, people always walk around smoking wherever, I think because it's outside and not part of the actual park, people either don't care, don't think it's an issue, or don't realize there are designated sections in CityWalk as well.
All of the in-park smoking areas are in places that you never NEED to walk through to get to rides or shows, but a few of them, you might accidentally cut through if you don't know they are there.
IoA:
Marvel - deck with misting machines overlooking the bay, used to be a viewing platform for the Hulk coaster, but it is currently being upgraded
Toon area- near bathrooms on main walk, but kinda around the corner from the bathroom entrance, in a little dead-end area
Jurassic Park - in a little walk-through misting area (I believe near the Thunder Falls restaurant...can't remember. Again, it is not necessary to walk through here, but some do w/o realizing it's a smoking section until it's too late)
HP/Hogsmeade- it's technically outside the area, in between Lost Continent area and Hogsmeade, off to the left of the entrance archway and slightly round a corner
Dr Seuss area - it's in a little planter/garden niche that's off a walk walkway...again, you would only be around the smoke if you accidentally walked the wrong way
Studios:
the little park in front of the clock tower is a smoking area...you don't need to walk through here to get anywhere, but a lot of people cut through w/o realizing it's a smoking area until they get there
Hollywood area, there's a smoking section on a dead end alley
Near Fear Factor and the bathrooms there is a smoking area, but it is set back from bathroom entrance
Near MIB, there's a seating area in the back corner, away from ride entrance and exit, for smoking
Simpsons & Toon area, I can't remember where they are, but like I said, most of them you either have to look for or stubble across accidentally.
Universal has planned the areas out very well that no one HAS to walk through or even too terribly close to the areas. That being said, occasionally people stand just outside the area, or "make their own" when they don't care or can't find an area. TMs put a stop to this ASAP, if they see this.
This all comes as the experience of a former smoker at Uni (Went to Uni 5x as a smoker, and this year I was a former smoker who cannot stand even a whiff of smoke.)