Go to runnersworld.com, it has some 1/2 marathon specific stuff under the "training" tab.
Running is so mental...basically think "tough" and remember these quotes:
"Whoever said anybody has a right to give up?"
- Marian Wright Edelman
"Never, never, never give up."
- Winston Churchill
"Defeat is not the worst of failures. Not to have tried is the true failure."
- George E. Woodberry
"There's no substitute for guts."
- Paul Bear Bryant
"Pain is temporary. It may last a minute, or an hour, or a day, or a year, but eventually it will subside and something else will take its place. If I quit, however, it lasts forever."
– Lance Armstrong
"A lot of people run a race to see who is fastest. I run to see who has the most guts, who can punish himself into exhausting pace, and then at the end, punish himself even more."
- Steve Prefontaine