... In particular just removing the specular, bump and normal maps from character skins and clothing will make a huge difference and most viewers won't even notice them missing in the final render. .....
I always use two tools for a final render, because I render mainly on CPU because my GTX750ti does not really help with rendering - scene optimizer and the camera view optimizer. With the scene optimizer you can reduce texture, remove maps etc. and the camera view optimizer just removes with one click all objects that doesn't matter for your render but will eat your memory (for example a room behind a closed door in a scene that is loaded with the environment) - But I prefer only to reduce texture resolution and remove items that you don't see in the scene.
Problem with removing maps for me is that I see the differences in my render, because I can compare, but removing them is an option you have with the scene optimizer, too.