loose some weight as above or if you have any rusty brackets in your engine bay, take them off, sand them down and paint them to freshen it up abit. just small things like that i guess and a can or two of spray paint wont cost you much either.
failing that just give it a good clean. take all the wheels off and clean the arches, exhaust etc. thats what i would be doing if i had the time especially with the amount of salt that has been on the road recently.