First of all where and which countries you want to visit, make a list, Euro-rail gives you discount as per your age you can take 15-30 day pass depending on travel requirement, for visa you need to and from ticket, hostel booking detail, sponsor letter, submit document through VFS global, usually it takes 15 days time for visa, in interview you need to be firm with your answer a lil hesitation may lead to no visa for you as you are a teenager, most important if an adult accompanies you it's easier to get visa, on another hand the country you land first will take your interview so chose wisely the country of visit.. hope it answers your query..