the best focus/meditation I ever found was fly fishing in Colorado below this dam... the fish were on myses shrimp(little clear fresh water shrimp).. that's why they were so big..

The shrimp were mid water so you had to really concentrate to see them... and you'd see the fish move over to take you fly...I'd stand there for 8 hours in a trance watching these fish...and would be pretty calm when I left...