It depends on your interests and the duration of your stay, but here's a suggested itinerary for a 5-day trip in Tokyo:
Day 1: Explore Shibuya and Shinjuku. Visit the famous Shibuya Crossing and do some shopping in Shinjuku.
Day 2: Visit the Tokyo Skytree, the tallest tower in Japan. Take a walk in Asakusa and visit the Senso-ji Temple, the oldest temple in Tokyo.
Day 3: Visit Tokyo Disneyland or DisneySea, or take a day trip to Kamakura to see the Great Buddha.
Day 4: Explore the Imperial Palace and its East Gardens. Visit the iconic Meiji Shrine. Walk around the fashionable Omotesando and Harajuku neighborhoods.
Day 5: Visit the National Museum of Modern Art or the Edo-Tokyo Museum. Take a stroll in the Ueno Park and visit the Ueno Zoo or the Tokyo National Museum.
Keep in mind that these are just suggestions and you can modify or extend the itinerary as you see fit. There's a lot to see and do in Tokyo, so plan ahead and make the most of your trip!