When you get back from your trip, try to continue being observant and open minded. Many of the stimuli of observation which have kept you going for the past several months will still be active, and can be applied to your home country. You’ll notice things that you wouldn’t normally notice. For example, the most striking thing to me when I landed at LAX after 8 months out of the country was the abundance of spoken Spanish, a language I had not heard for quite some time. Keep your journal going for a few days and try to draw comparisons and differences between home and the places you've just visited. Do you notice anything that your country lacks? It’s these types of observations that will make you appear "worldly" to others. Take advantage of this window of opportunity while your mind is still in a state of flux.
If you're committed to not letting your trip slip away from memory, work with your photos and journal to help educate others. You've just spent a significant portion of your life traveling around places that are totally foreign and inconceivable to many people around you. Consider it your duty to properly inform others, to get misconceptions out of their heads. Tell them how friendly the people are, how tasty the food is, and how safe the streets are. Better yet, tell them your own conclusions. Organize slide presentations for your school, workplace or even just for your friends and family. As soon as your film is developed, write down the date, subject and location of each photo, with as much detail about everything visible as possible, while it's still fresh in your mind. Use your guidebooks and journal to help refresh your memory. Write up and expand on some of your ideas in your journal, either in an attempt to benefit others and make money (publication) or even just to formalize and sort out your own ideas (which is exactly how this guide started out). You'll be glad years down the road when you have photos and writings to reflect on. Nothing sucks more than letting an awesome experience slip away.
Finally, don’t be discouraged when you realize that most people back home don’t care about all the cool, life-changing world travels you’ve just returned from. Things that are totally foreign, inconceivable concepts tend to bore people easily. Their initial questions and curiosity will fade quickly. You’ve taken the time to learn about the world on a personal level, so consider it your gain, and their loss, and revel in the pleasure of knowing that you know more about "lao-lao" than anyone else on the street. Hopefully, if you’ve piqued their curiosity in the slightest, they’ll be stimulated to think about the benefits of world travel for their own lives.
Now you know more about this than your friends.