If you don’t have the time to organise an itinerary or are afraid as this is your first trip overseas then a tour may be the thing for you. There are quite a few different tour operators depending on where in the world your wanting to go.
The above seem to be the best indexed sites of tours that I could find, but there are plenty of other tour operators within niche markets such as singles travel, adventure travel, 18-35 travel, seniors travel, gay and lesbian travel, etc.
One company that comes highly recommended and offers a wide range of tours that cater to just about all needs is My Adventure Store. They have a great specials section with deep discounts for last-minute tours, and even offer the ability to communicate directly with their “adventure experts” to ask questions about the tour beforehand.
Your best source of information is going to be word-of-mouth (a positive word or two from a friend can go a long way!) You can usually rely on reviews from sites like TripAdvisor and other review sites as well. Just be sure to read the negative reviews with a grain of salt. While most are legitimate, some are posted by competing tour companies, and still others are posted by folks who just never have anything positive to say about anything. A group tour is what you make it, and while to some degree the experience does depend on the people in your group and the tour guide, your attitude and reaction to events is going to be the deciding factor on whether the experience is positive or negative.