There's a few things you can do, but only if you do a total "basjoos" to your car's body (look up his name and car) will you gain more than plain old smart driving. You can't do much real 'adjusting' to the engine itself, other than synthetic oil, unless you have a good friend who has a car computer programmer that knows what he's doing. (Other modders insert arguments here...
) Otherwise it would be forever getting the money involved back out of it. A couple of starter things to do are keep the tire pressures up at the max on the sidewall, narrower tires when you replace them, keeping all of the extra junk (weight!) out of the back seat and trunk, and then the simple aero mods that most of us can do. I bought some .060 Lexan on eBay, and blocked off my bumper holes, since most of the air to the radiator channels in from the air dam under the front of my Intrigue. If your Acura still has a functional opening above the bumper, you could do a similar thing below the bumper. For the bumper block I started by cutting out cardboard to get the right size, and then cut the .060 (1/16) Lexan with tin snips. 4 screws held it down, see the first pic. Then I used the rest of the piece (a 4 foot by 8 inch to start out), cut it in two, and extended my air dam out to the edge of the fenders. I heated and bent the last inch over to screw it to the inner fender mount in front the tire. (second pic. Never mind the poor quality...) I used Wal-Mart Krylon flat black to spray the extensions to the air dam, and left the bumper block clear.
That same sized piece might just work under the bumper of your Acura, with just a little trimming.
With (and beyond) that, you'll just about have to read what others have done, and see if it's something you can do or not to your car. Mileage improvements vary greatly with these. You'll need to average a few tanks fills after each modding, since there's too many other variables involved to know for sure right off how much it helped.