7D not sharp???

Hi all

I have had my 7D for about 6 months now and TBH I am not happy about the clarity or sharpness of the photos that it has produced. I had the crammer on a tripod today taking shots of a waterfall and quite a few were not sharp which I am beginning to find annoying.

I wonder (I am a noob) if I am not using the correct focusing mode and wondered what everyone else finds what works for them.

JOHN