A good first-impression destination for Beijing, and an infamous one at that, is Tiananmen Square. There's not much to see on the square itself - it's really just a huge plaza. But it gives you an inkling of the sheer size of monuments - even a public plaza - that Beijing offers. Of course, millions of people paraded through the square on occasion under Chairman Mao and the Square became famous in the West in 1989 as the news broadcast the army clashing against pro-democracy demonstrations. Now it's a place for kite flying and strolling - bikes must be walked across the square. The square is surrounded by heavy Communist monuments such as the Chinese Revolution History Museum and the Great Hall of the People.
Worth a stop if you have a vague interest in seeing embalmed Communist leaders, is the Mao Mausoleum. There will be an enormous line to get in so you'll have to wait, and make sure to bring your passport. The line moves fast; people are shuffled quickly past the Chairman's embalmed body.
Lunch Break: It's your first day and if you can't stop sight-seeing to eat, bring along some snacks or a packed lunch from your hotel. There are plenty of spots to stop and rest in the Forbidden City. There aren't a lot of lunch choices once you're inside. Stop in the snack bar or restaurant at the Great Hall of the People before heading off to the Forbidden City.