Tokyo Tower is just a 10 minute walk from Hamamatsucho Station. Take the North Exit from Hamamatsucho Station, and as soon as you exit, you will see Tokyo Tower in front of you. Walk straight toward the tower for about five minutes, and you will see the entance to Zojo-ji Temple. Enter the temple grounds continuing straight, walking around the temple, and after a further five minutes, you will exit the temple grounds and arrive at Tokyo Tower.
From Tokyo Station to Hamamatsucho Station:
Take the Yamanote Line direct to Hamamatsucho Station (6 minutes, ¥160)
From Shinjuku Station to Hamamatsucho Station:
Take the Yamanote Line direct to Hamamatsucho Station (27 minutes, ¥200)