Although Glenn mentioned it above, we don't think it has been made clear that ALL of the electoral votes in each state are (generally) awarded to the candidate that gets the most votes in that state. So, if one candidate gets 51% of the popular vote in a state, he gets all of that state's electoral votes.

The reason this is so important is that most states traditionally vote for one party or the other and can be counted on to be "red states" or "blue states". For example, California, New York and Massachusetts can be relied upon to go to the Democrat while Texas, Georgia, Mississippi and Alabama consistently vote for the Republican.
So, very little effort is spent campaigning in those states because the outcome is nearly certain.

On the other hand, there are a few states (about 10) which are considered tossup or battleground states. These include Ohio, Florida, New Hampshire, North Carolina, Iowa, Nevada, Colorado, and Virginia and maybe a couple of others. Nearly all the effort is devoted to winning these states because that's where the action is. If you live in one of these battleground states, you will see hundreds of political adverts on TV until you are utterly sick of them. There is a TV station in Las Vegas, Nevada which stated recently that it had run more than 20,000 political ads this year and that was a few weeks ago.

Bev and Jerry