Notify your credit card holder before you travel. Credit card companies and banks will deny charges from other locals, especially overseas, to protect you from identity thief. They will lock you card number until you contact them.
Let your neighbors know you are on vacation and how to contact you. Arrange for someone to check on your home.
Contact your cell phone carrier to ask questions about coverage overseas or out of your home area.
Think about your presciptions and any special medical needs you may have before you leave.