What are some examples that show that Jack thinks of himself higher than the other boys on the island?

First of all, Jack believes (and says so) from the
beginning that he thinks he should be chief. He believes the Hunters are most beneficial
to the group because they get meat for everyone, and since he is head of the Hunters,
that he is naturally the best.

He felt he and his hunters
were too good to tend the fire, so they let it go out as they were off trying to kill
pigs.

He also puts others down (especially Piggy) through
name calling and violence. Bullies often pick on those they feel are inferior to
them.

He sets himself up as a king of sorts in a fortress
on the rocky side of the island and keeps the others in line through
beatings.

But, I think, the ultimate "better than you" move
is when he actually treated Ralph like an animal and "sharpened a stick at both ends" to
eventually put Ralph's head on it as an offering to the beast.