Push/Pull is exactly what it sounds like. Perform one exercise that requires a push movement, like bench press. Then move on to an exercise that requires a pull, like rows. Simply put, anything involving biceps is considered a pull. I'm not sure if a push/pull philosophy would work in EVERY circumstance, but you don't need to make lifting complicated. Push/Pull isn't superior to anything else, supersets, drop sets, forced reps, they all have their place. The principle to success in bodybuilding is variation. Variation in exercises, Variation in frequency, volume & intensity, rest.
I'll emphasize volume & intensity (sets x reps & amount of weight). Adjusting this will have an emphasis on the type of adaption(s) your body makes in response to your program, muscular, neural and endocrinological ("emphasis" on growth hormone or testosterone).
