The best travel itinerary for Iceland depends on your personal interests and the amount of time you have to spend in the country. However, here's a popular itinerary that covers many of Iceland's must-see destinations:
Day 1: Arrive in Reykjavik and explore the city
Day 2: Drive the Golden Circle and visit the Thingvellir National Park, the Geysir hot springs, and the Gullfoss waterfall.
Day 3: Take a dip in the Blue Lagoon and visit the nearby lava fields.
Day 4: Head to the south coast and visit the Skaftafell National Park and the Jokulsarlon Glacier Lagoon.
Day 5: Continue east and visit the Vatnajokull National Park, with opportunities to hike on the glacier or go ice climbing.
Day 6: Drive the Ring Road and stop at various waterfalls, hot springs, and other scenic spots along the way.
Day 7: Return to Reykjavik and enjoy the city's cultural and nightlife.
Note that this itinerary assumes 7 full days in Iceland, and can be modified to fit your specific needs and interests. Also, be mindful of weather conditions, road closures, and other factors that may impact your travel plans.