Training in relation to deep water soloing is a loose term indeed: this article merely offers a few mental training ideas and principles. It assumes a basic knowledge of general rock climbing and good stamina levels, which invariably prove more useful than outright power.
Specific notions about training for DWS usually come back to the more general 'head game' of traditional climbing, and work on the principle that you don't have to be outrageously strong if you have a good head. An anxious leader will often pull far too hard on the holds and not use his or her feet sufficiently: this is acutely apparent in DWS, where there is no safety net in place whatsoever.
Assuming a general fitness in climbing, the very best a potential deep water soloist can do is to get comfortable with his surroundings, and to that end he or she must somehow make themselves comfortable above water. This is everything!
A few key hints: