Sure, here's an ideal itinerary for 1 day in Thanjavur:

Morning: Start your day with a visit to the Brihadeeswarar Temple, one of the most iconic landmarks of Thanjavur. This temple is dedicated to Lord Shiva and is known for its stunning architecture and intricate carvings. Spend some time exploring the temple complex and admiring the towering gopuram.

Afternoon: Next, head to the Thanjavur Palace, which was once the residence of the Nayak and Maratha rulers of Thanjavur. The palace complex includes several buildings, courtyards, and gardens, and is a great place to learn about the history and culture of the region. Don't miss the Saraswathi Mahal Library, which houses a vast collection of ancient manuscripts and books.

Evening: In the evening, take a stroll through the local markets and bazaars, where you can shop for souvenirs, handicrafts, and traditional textiles. Thanjavur is famous for its silk sarees, so be sure to check out some of the local shops. You can also sample some of the delicious local cuisine at one of the many street food stalls or restaurants in the area.

Night: End your day with a visit to the Sangeetha Mahal, a beautiful auditorium that hosts classical music and dance performances. Check the schedule beforehand to see if there are any shows happening during your visit. Alternatively, you can simply relax and unwind at your hotel, ready for another day of exploring tomorrow.