I run a hostel for backpackers in Sri Lanka.
The day to day work is mostly the fun stuff: talking to guests from all over the world and helping them plan their trips in the country. However I have a lot of work managing reservations, availability, and rates on the computer and keeping my accounts up to date. This is more behind the scenes that most people wouldn't know I do.
Being open to new cultures and having excellent interpersonal skills are the most important things that are needed for this job. My experience was not the reason I got the job, nor did it really help me get started in the job. Being flexible and learning on the go from the other people that were here before me was the best training I could have gotten.
Here's the first step for high school students
Get out and explore the world after/during high school. There are so many opportunities that you can find in high school, university, and on your own time. I did an exchange in middle school plus a year abroad in university, plus I went to a boarding school in another country for my last 2 years of high school. Most hostels don't require you to have any experience to work and many places will let you volunteer your time in exchange for a free place to sleep.