Mesomorphs adapt quickly to exercise and you need to maintain variety in your workouts to keep stimulating and challenging your muscle. Maintaining variety also helps mesomorphs reduce injuries and maximize gains. As part of this you add new exercises or simply change the order of your exercises.
Although, you have excellent natural strength, keep workouts under one hour. Do not over-train. Pay proper attention to rest and nutrition to get the most out of your efforts. Other effective exercise strategies for mesomorphs include circuit training and high-intensity cardio (e.g. HIIT) to burn fat, whilst building muscle.
To increase strength and size. Perform 8-12 reps with moderate-to-heavy weight and at lest 3 sets of each exercise, with 30-90 seconds rest between sets. Complete 3 exercises per muscle group.
To increase strength without building muscle mass. Train 2-3 times a week with using higher reps with lighter weights. Do 3 sets of about 15 repetitions using light to moderate weights or just bodyweight. Circuit training and super sets, build strength and stamina, but increasing mass.
Perform cardio preferably 5 times a week: