Muscle mass can be increased with the help of additional weight through so-called resistance training, which means that muscles have to overcome certain weight (resistance) in order to complete the exercise motion. With weight lifting the number of muscle cells and fibers increase allowing the space between the cells to widen and that is what crates bulked up effect. The muscle contraction needed for weight lifting should be fast and explosive so that there is not enough time for oxygen to get included in the muscle contraction process. Because of this, lactic acid accumulates and that induces exhaustion of the muscles. That is why weight lifting usually has not more than 12 repetitions in a set.
When a muscle is built, it can be done with focusing on one muscle group or several at the same time. Lately, people use more exercises that emphasize more than one region simply because it saves time and it might be better for the overall strength of the organism. For example, performing squats with a barbell is a form that activates several muscle groups and is a very effective technique. There are certain muscle groups that people generally like to emphasize on during their workout. Those are biceps, abs, latissimus, shoulders, quads etc.
Good bicep exercises should be performed in a standing position. In this way, a proper posture is also exercised. Most popular exercise is a bicep curl, which can be done with barbells or dumbbells. Important thing is, always keep your torso steady so that the entire weight is lifted with hands (biceps) only. Elbows must be fixed too, next to torso sides but without leaning, because that will make exercising easier.
Push up is also an effective exercise, although only torso weight is lifted. Push ups cannot be upgraded due to not being able to add more weight. Adding weight is necessary for keeping the muscle mass growth constant and steady. At some point, when the same weight is used for a while, the exercise becomes easier and the wanted results are not coming. In those moments, the weight used has to be increased. For further enhancement of the muscle growth, supplements need to be taken, either muscle growth inducers, energy boosters, or fat burners.