I'm a lawyer who does nothing but defend an insurance company in workers compensation proceedings. Being successful at least for me requires overpreparation. Like maniacal overpreparation. This can be exhausting but you will rarely if ever get caught in a bad spot and you will be able to anticipate just about anything. It's like anything else...hard work and hours are the answer. I've found that when you develop a reputation of forcing the opponent to really work to get something it is alot easier to get stuff done quickly.