um...I'm a newbie, and this is my first auction...can you guys help me to understand?

my first auction are about a lot of books and I really want to win it. How do you snipe?

Can you help me on this topic...example: I keep getting outbid. I bid 10$, but a person bids higher, let's say, 15$. I don't know it of course, so I bid 20$. And then I won the auction. How much will I pay? 20$? or 15$, or 15.50$?

Can someone give me a crash course on what to do? The auction ends on Monday, around 5:50-6:10 am. i don't live in the US so it is likeley that the person I am bidding against is in another time zone...any advice how to win a first auction???

help would really be appreciated...wish me luck!

Thanks for those who'll reply!