#1 When booking flights and hotels online enable private browsing. Travel sites often track your visits and will raise the price simply because you've visited before.
#2 When reserving seats for two people, choose the aisle and window seats. If no one takes the middle seat, then you get the full row, and if someone does, then just ask to switch seats so you can sit next to your partner.
#3 Put enough clothes in your carry-on bags for the first day or 2 of your trip. On long flights with multiple stopovers, packing a fresh change of clothes is a good idea as bags tend to get delayed or lost on long haul, multiple stop flights. You don't want to be hunting for a pair of shorts immediately after your arrival in a new city or country.
#4 Avoid jet lag by getting plenty of exercise the day before you leave, which will also help you sleep on the plane. When you arrive in your destination, get plenty of fresh air, to further stave off jet lag.
#5 Have a secret stash of spare cash rolled up in an empty lip balm tube or lipstick.
#6 Send a postcard to yourself back home each day of your holiday. It'll be a nice surprise to come home to, and you can add them to any travel memory montage you create!
#7 Take photos, not photocopies, of your documents and email them to yourself. Will help you a lot if you loose any important documents or your bag on your travels.
#8 If you need someone to take a photo for you on holiday, pick a family with kids. They're almost guaranteed not to make off with your camera!
#9 On the last day of your trip to a foreign country, collect all of your loose change and give it to the homeless.
#10 Make friends with a local! Why do you travel in the first place? To experience the culture of wherever you're going, right? If you want to experience a place like a local, you could spend some time asking the bar staff where the best restaurants and pubs are, but you could also actually have them show you around.