First off, I'd recommend not visiting Beijing in the dead of summer. It was incredibly hot and humid and it was so insanely crowded at every sight we saw. That being said, summer was my chance to go, so I went.
I was traveling by myself and didn't want to deal with the hassle of trying to get to farther sights like the Great Wall at Mutianyu and the Summer Palace on my own, so I decided to book a two day small group tour. This was truly the best option for me and I'm so glad I did it, because I ended up with a really great group and we were able to take photos of each other and keep each other company on some of the longer car rides. The other best part was the guide we had for the tour. Her name was Sunny and she was excellent. She spoke perfect English and she had clearly been doing this for a long time, so she had all the tips and tricks and so many stories and facts to tell us, so she was really invaluable. You can contact her here (and I swear I wasn't paid to say this, but she really was awesome and truly recommend her as a guide).
On our first day, Sunny and our driver picked everyone up from our hotels and dropped us off at our first stop - Tiananmen Square. The square is truly massive and interestingly is the most important location for Chinese tourists to visit. There's a flag raising ceremony every morning at sunrise and people will camp out for hours to get a good spot to watch the ceremony every day. It's truly amazing. From the square, you can see the entrance to the Forbidden City/Imperial Palace and it's quite the sight to behold. The square is surrounded by government buildings and also the National Museum of China, which I didn't have a chance to visit, but I heard it's amazing.