I'm trying to use precompiled headers to accelerate the compilation process.

I've found some articles about it, e.g.,
However, I need some step-by-step tutorial.

I've tried to g++ -c *.h in my current project folder,
I got some *.pch, however, when I build the project again,
I can't fell any performance gain.
(-fpch-preprocess flag also used in the re-compiling)

The bottleneck should be files I included in the /usr/include
So, should I go there and then sudo g++ -c *.h?
I guess this is not the case...

Thanks in advance.