Check the include path for the compiler. The directory where the file is must be included in it. I think on most compilers you do that by passing the command line parameter
Did you copy all of SFML's static library (.a/.lib) files into the directory where your compiler is trying to find them? The directory probably looks something like "C:/mingw/lib/", or wherever you have mingw installed.
Alright, I changed the LIBS variable as so LIBS = -L/usr/local/lib/ -lsfml-system -lsfml-window -lsfml-graphics
But still get the error messages "cannot find..."