1. Choose an activity very touristic so you can pay 10 times the price.
2. Choose the date of the excursion without watching the weather forecast and count on your bad luck for the rain or storm.
3. Choose an activity that is painful, or even better, that requires physical preparation, so you'll be assured to suffer a big deal.
4. Make sure you have to wake up very very early so you'll be tired from the beginning.
5. Go with people you can't stand. The best are the ones who know everything, have seen everything and can't wait to tell you.
6. Choose a guide who consider you as a "wallet-on-feet", just to pay a bit more.
7. If there is an outfit required, IGNORE it.
8. Make hundreds of photos, with you on it, to show to your friends you did it and how wonderful it was.
9. Make sure you get sick, by food or cold for example, so you'll remember this experience for a few more days.
10. If your visit can have an impact on the local ecosystem, it's a bonus.

I recently applied a few of these guidelines and succeeded in becoming a perfect "tourist-looser"...
My hostal mates convinced me to go with them and climb Chimborazo. A beautiful snowy volcano. So by a wonderful stormy day, we woke up at 5am to hike from 3200m to 4850m.
We didn't see anything but fog and icy wind. Got sick due to the 7 hours of being wet and cold. Even my bones were cold!..
What a wonderful experience! :)