Make sure your home life is set up so that things don't collapse while you're gone. If you're single, make sure your mail gets taken in (or get a PO Box), your plants get watered, your pets get fed, etc. If you're married, figure out how to handle administrative conversations -- bill paying, grocery shopping, etc. -- remotely. When you're home, you want to spend quality time with your spouse instead of getting bogged down in that stuff.
Take care of yourself while traveling. Figure out how to take your exercise routine with you, eat healthy meals at reasonable times, etc. Wash your hands often and be really paranoid about food-borne illnesses. Being sick is bad enough, but being sick 3000 miles from home is really horrible.
Pack a "go" bag with duplicates of your absolute necessities. (Medications, contact lenses, toothbrush, clean underwear, cash for cab fare.) Keep that in your laptop bag, carry on, or wherever it will be impossible to leave behind.
Get a travel alarm or traveling clock radio. *Always* use it, not the alarm supplied by the hotel. This one sounds trivial, but it's amazing how much a familiar alarm sound can help you orient yourself in a strange place. For the same reason, if you travel internationally invest in a world band radio to keep you in touch with home.
Katherine