Check the weather.  Find out what to expect and pack accordingly.

Ask your credit card company about your spending maximum and request an increase if you think it will be necessary.  Remember, any deposits will be charged up front, so leave room on the card for emergencies or extra spending.

Check the expiration date on any credit cards you plan to use.  Make sure that they be valid while you’re traveling.

It's not a bad idea to notify the credit card companies that you’ll be traveling, especially if it will be out of the country.  That way they will know to expect charges from unusual locations.

Verify both your ATM and debit cards for daily and total limits.

Write down your PIN numbers and keep them safe.  You may want to get new ones issued as an extra safety precaution.

Buy and install automatic light timers for your home, that switch on and off in the evening.

Check your driver’s license to make sure that it will remain valid while you’re traveling.

Buy batteries for any cameras that you will be taking and a good supply of film.

Arrange for a neighbor, friend or relative to check your home occasionally while you are gone.

If someone can't pick up your mail, ask for it to be held at the Post Office.

Arrange for lawn care or snow removal as needed.  If you ignore things like that it will make your house stand out.   It really announces to anyone that no one is at home.

Have someone start your car during very cold or very hot weather.

Make arrangement for pet care.

Break in any new shoes that you’ll be taking on the trip.

Consider using yogurt in your diet to strengthen your digestive and immune system.  If your plans include travel within foreign countries, this can be especially important.  You may be exposed to elements that are hostile or negative to your system.