Yes it is crucial to include heavy exercises to get big arms. But these should be compound exercises that utilize the large muscles of the torso as well. The muscles of the arm are still involved in these movements and still get significant stimulation.
Rather than a heavy bicep curls, try heavy supine rows for 5-7 reps. Maintaining high intensity within this rep range will cause the desired endocrine response because more muscle fibres are activated than in isolation exercises. A great compound exercises for the triceps is strict dips for 5-7 reps. Add weight using a belt if you are a beast and need more resistance
Of course, you will want to include isolation exercises to get maximum pump. But the point here is VOLUME, NOT STRENGTH. You will have to leave your ego at the door if you want to actually achieve a euphoric hypertrophy pump. Sure you might look cool reefing on the 60 pound dumbbell. But it is not going to give you the biceps you want, and is most likely to just destroy the elbow or joint.
Never forget, the amount of blood you can force into a muscle is directly proportional to the size of the muscle. So how do we go about achieving this? The best way is to use the cable machines after the heavy compound exercises. Constant tension can be maintained throughout the movement, resulting in max pump. But, if you are going to hit the 8-12 rep range correctly, the amount of weight used must be sacrificed. As a general rule of thumb, you should use 70-75% of your max intensity. Focus on the last 2-3 reps as controlled as possible while squeezing the target muscle as hard as possible.
Slowing down the reps at the end of a set will put more emphasis on form and will increase time under tension (TUT). Ultimately, TUT is the major factor when it comes to increasing the size of a muscle. There are obviously 2 important variables here. Hypertrophy sets should last at least 30s, up to 60s. The more forceful a muscle can contract, the more tension it is going to have. Rather than increasing the weight to achieve this, try actually full activation the entire muscle with a lighter weight.
If you are training correctly, you would need to devote too many sets towards direct forearm training because they should get plenty of stimulation by exercises such as deadlifts, pullups and rows. Wrist curls can be very dangerous, especially in high rep ranges. Therefore, it is best to limit the sets of wrist curls. Rather than focusing on the wrist, focus on grip strength to build the forearms.
The most effective way to develop grip strength is to simply hold heavy dumbbells. This is known as the farmers walk, but without the walking. If your gym has a hex bar, use it because you can safely load it with a lot more weight than dumbbells. Aim for 30s holds with as much weight as possible.
In review, start with heavy compound exercises and include isolation exercises using the cable machine. Finish your arm day by focusing on grip strength. This will give you the strong, well defined arms that will make the ladies unable to look away.