If like most people you are eating once or twice a day or relying on fast foods to get by, then a bodybuilding diet may be absolutely different to what you are used to. If this is the case, then it is best to follow the steps provided in my article Easing Into A Bodybuilding Diet so that you slowly start changing your eating habits into the ones required to be successful at bodybuilding.
When lifting it is essential to focus your mind completely on the muscle group you are attempting to work on. This makes sure that you are actually using the target muscle to lift the weight rather than accessory muscles or even momentum. This skill will develop with time, and as you progress in making that mind to muscle connection, your workouts will become much more productive and efficient.