If you’ve only got two days in Luxor, your schedule will be full on. Start the first day on the east bank with an early morning visit to the Temples of Karnak. After Karnak stroll along the corniche to the Luxor Museum. After a late lunch at Sofra, visit Luxor Temple in the golden glow of the afternoon. Return after dinner to see the temple floodlit. The next day take a taxi for a day to the west bank, starting early again to avoid the crowds at the Valley of the Kings. On the way back visit Howard Carter’s House, with its brilliant replica of Tutankhamun's burial chamber, and the Memorial Temple of Hatshepsut. After lunch visit the Tombs of the Nobles, or the wonderful temple of Ramses III at Medinat Habu.
Four days allows for a more leisurely schedule. On the west bank, you could visit the Tombs of the Nobles, the Ramesseum and the Temple of Seti I, and on the last day revisit Karnak in the morning and cross the river to see the ancient workers' village and tombs at Deir Al Medina. Alternatively you could make a day-trip to the amazing temples of Dendara and Abydos.