On Sunday, I sent my Coolum new route, Grazed Anatomy. The key to unlocking this route was building the strength to get through the hard bouldering in the first half of the route efficiently, as well as learning how to get the most from the rests on the route (there's a sit-down rest as well as several kneebars!). The only real way of doing this was trying the route repeatedly to build up route-specific strength and endurance.
During the couple of weeks I was focussed on this route, I was careful in my other training to focus on short, hard training (anaerobic endurance), rather than endless laps on easier things (resistance).
Generally, your training should mimic the kind of routes you want to do.