when you did the carbon fiber for the first time you had to make the pattern right? you go to file - new ..........
when you make the new document you have to fill in the width and height of it. to make the pattern smaller just set the height and width lower till it`s right.
you can also make them smaller using edit - transform - scale
or edit - transform - skew
use scale and skew after you filled the layer with the carbon pattern.
read the tutorials some more, to make it look good. You need to make another layer over or under the carbon layer and adjust it to make it look darker and you have to do some stuff with the blending modes of the layers. It`s all there in the tuts just read it carefully