Mahakaleshwar Jyotirlinga Temple is one of the twelve Jyotirlingas in India. Morning is the best time to visit as it is less crowded. Here you can witness the famous Bhasma Aarti, which takes place at 4 AM and is a must-see. The temple opens at 3 AM and closes at 11 PM. Afternoon, you could visit the Vikram Kirti Mandir Museum (3.5 km from the temple). This museum is dedicated to the life of King Vikramaditya and showcases his cultural and historical contribution. In the evening, you could go to the Kaliadeh Palace (8.4 km from the museum) situated on the banks of the Shipra River. It is a perfect place to relax and enjoy the beautiful sunset.
In the morning, you could visit the Sandipani Ashram (4.3 km from your hotel). This ashram is famous for being the place where Lord Krishna and Sudama studied under Guru Sandipani. Afternoon, you could visit the ISKCON Temple (8.4 km from the ashram). This temple is dedicated to Lord Krishna and Radha. It is a place of peace and serenity where you can experience the joy of devotion. In the evening, you could visit the Kal Bhairav Temple (3.7 km from ISKCON Temple), dedicated to Lord Shiva. It is believed that a trip to Mahakaleshwar Temple is incomplete without visiting this temple.
There are many other places to visit in Ujjain, such as the Harsiddhi Temple, Navagraha Mandir, and Ram Ghat. You could also take a side trip to Omkareshwar (146 km), a sacred island situated on the Narmada River. To maximize your fun, you could try the local street food, which is famous for its taste and variety. You could also participate in the various festivals celebrated in Ujjain, such as the Kumbh Mela, Shivratri, and Navratri. Lastly, I suggest you book your hotels and flights in advance using this link.