I had to sit in the back row of the large lecture hall, where I could barely see the calculations on the board and could hardly hear my professor. Even if you miss the first five minutes of lecture, it can become very confusing and difficult to catch up. And, you don't want the worst seat in the room. Dozing off right in front of the professor is the worst impression you can make. Also, students tend to focus better, because of fewer distractions, if they sit closer to the professor.
Professors tend to remember the faces of students who sit in the front row.
Introduce yourself to your professor as soon as possible. A professor is more willing to help you if he knows your name. Meet as many people as you can. Introduce yourself to as many classmates as you can. I had a buddy in Biology, last year, who would let me copy her notes when I was sick and missed class.