1) Something bad happens over the summer that makes Harry anxious to begin the school year.
2) Big deals are made about arriving at Hogwarts.
3) Various things go on around the different holidays.
4) Some kind of hubaloo about Quidditch.
5) Snape acts like a snobby jerk.
6) Malfoy acts like an evil jerk.
7) Hermione knows more than everyone else.
8) Dumbledore is aloof and mysterious.
9) Hagrid makes a big deal out of some dangerous critter only he can love.
10) Various weird things happen in and out of all of the above that make people immensely scared yet seem to be forgotten in favor of the above sub-plots.
11) In the end it all turns out to be Voldemort.
Now, go write something famous.
Taken from here.