If you are traveling by train or plane, I find that a long plane or train ride is the perfect time to catch up on reading. No phone or email or Internet to distract you. (Yes, I know that many planes offer wifi in the air, but why pay to be more distracted?) I will carry a book or two I've been meaning to read.

• There are two good ways to keep from having to carry heavy books. First, use e-books. Many libraries lend out e-books that you can read on a phone or tablet. Increasingly, airlines (especially on longer flights) offer USB ports for recharging. You can download a vacation's worth of beach reading onto a device that weighs less than 2 pounds. Second, buy used books and leave them behind as you read them. I've passed on books to flight attendants and left them in libraries at resorts and B&Bs.
• Children can read or watch videos or play games on a tablet. Be sure to pack ear buds. Your fellow passengers thank you.
• Carry old magazines that you can discard as you read them.
• Nap.
• Hand write personal letters.
• Crochet or do needlework. Crochet hooks pass through security easily, as does needlework as long as you remember to bring short-bladed safety scissors.
• On the way home, I take time to organize my receipts for Customs.

If you are traveling by car (and you are not the driver):

• Books on tape are a good idea. Many libraries loan out audio books. Look for family favorites or books set in your destination.
• Play classic car games like "I Spy" and the license plate game.
• Consider investing in travel games like Scrabble, backgammon, checkers, and the like.
• Crocheting and knitting do well in the car.
• Watch the signs to look for interesting places to stop.
• You'll notice that watching DVDs or playing video games are not on this list. We all have more than enough screen time the rest of the year. When there are other things to see and do, why not?

Spend some time before your trip researching your destination either through guidebooks or on the Internet. Pick a limited number of destinations (less than 10) that are absolute must-sees.

• Print out or purchase a good map of your destination and spend some time familiarizing yourself with the location of your hotel and getting a basic sense of the city's layout. You may get lost (that's how I found the most luscious cream tea in Oxford), but you don't want to wander into a dangerous part of town.
• If there are some things you really want to see, make reservations before you leave. DO NOT over schedule. You don't want to spend so much time running around that you are more exhausted when you get home than you were when you left.
• Leave time for just wandering about, enjoying your surroundings.
• Take at least a day to live like the locals. Maybe spend an afternoon at an outdoor café or walking through a park.
• Try to plan different types of activities: some physical activities like hikes or long walks — or take advantage of local athletic activities like zip-lining or boating; some cultural activities, like museums or concerts; some intellectual activities, like museums and historic sites; and, some fun, like local eateries and shopping.
• Have some basic plans, but stay flexible so that you can take advantage of opportunities as they arise.
• As you wander about, keep an eye out for posters and other announcements. You may find the most amazing opportunities.
• Have an option or two in your back pocket just in case the weather is bad.
• Carry a few cards with the name, address, and phone number of the place where you are staying in the local language. If you get lost, you can hand the card to a taxi driver. 
• Go a little bit outside your comfort zone. So you look silly? You'll never see these people again anyway. Why do you care what they think?