Hello - I was painting a greyscale portrait and I haven't started in colour yet...

I felt my portrait (bottom one) looked a bit too smoothed out - and then I saw these two pieces:

http://itchstudios.com/psg/tuts/organic3c2.jpg
http://itchstudios.com/psg/misc3/GreyChitinoid6.jpg

I quite like the noticeable big hard brush strokes - I try to do this with my portrait very quickly:

Messy Strokes - Brush stroke tips?


I prefer the top one as it kind of mimics the style of the two images (above) - is there any way I can improve on this, or read upon such a technique? Thanks!