Eighteen-year-old Matena Barry, from Edward M. Kennedy Academy for Health Careers, has some weird and some, OK, over-the-top-weird obsessions. One of Barry’s many obsessions is that she cannot sleep without the sound of an air conditioner. No matter how cold it is she has to have it on before she can doze off. It gets so bad that, during the winter, Barry says she takes the AC out of the window so it won’t get damaged by the snow and just sets it down on the floor and plugs it in. Meanwhile, Nadia Singh, 16, is fixated on food. “I even dream about food -- well, fried chicken mainly,” says Singh, from Boston Community Leadership Academy. “It’s weird, I know, to dream about food, but I do.” For Kadidiatou Bah, 15, as long as it’s sweet and edible she is quite all right. “Candy will be the death of me,” says Bah, from Health Careers Academy. “I just can’t live without it.” Bah is stuck on candy and treats it as a special food instead of just a once-in-a-while treat. “I’m telling you, in health class they missed a food group,” says Bah. “Candy is a food group.”

From liquid to powder, lining your eyes is an art that is hard to master. “Putting on eyeliner is pretty difficult because it takes a steady hand, practice, and attention for detail,” says 15-year-old Jamie Weisenberg, from Boston Latin School. To the rescue are the famed beauty gurus, fashion teachers who use YouTube as their classrooms, filming makeup, hair, and nail tutorials; DIYs; reviews; and beauty hauls. These fashion “experts” range from professional makeup artists to common, everyday people. Among the faddy favorites are Michelle Phan, a makeup artist who now has her own cosmetics line; “Bubz” of bubzbeauty; and Leina of the MakeupByLeinaBaaaby channel, famous for her celebrity-look offerings. The guru world is not exclusive to adults. Teens have become media stars for their beauty advice, including California girl Bethany Mota and the dearly missed Talia Castellano, cut down by cancer this summer at the age of 13. The videos can aid beginners who are new to the makeup world. “I never really knew how to do it before,” says Frannie Murphy, a 15-year-old student from the John D. O’Bryant School of Math & Science. “It helped me figure out what goes where.” Murphy says the beauty-guru videos are not strict rules but rather a good source of inspiration. “Whenever I do it, I watch it, take an idea from it, and do my own thing,” says Murphy. Weisenberg says that these videos have a positive effect on teen’s creativity. “I think it inspires them to try something different,” says Weisenberg, a loyal fan of beauty guru MissJenFABULOUS. The videos also offer a venue for experimentation. “If you want to try something new, it’s easiest to learn online,” says Anneli Merivaara, 14, from BLS. Although popular, as with all YouTube videos there is a “dislike” button as well as a “like” one. Teens say that some of the gabby gurus’ tutorials are hard to recreate. After all, they say, not everyone has the same skills, products, or face. “The people who do the tutorials,” says Murphy, “make you think no matter who you are, it will all look the same.”

Ralph Karnuah, a senior at Brighton High School, believes in natural beauty. “I think it enhances your looks, but there are girls with short hair that are just as beautiful as girls with long hair,” says Karnuah. The style or length of your hair definitely defines your appearance. Seventeen-year-old Walae Hayek, from Brighton High, feels that the length of a female’s hair is a style statement. “Some girls may seem way more attractive with longer hair,” says Hayek. “Also, the public perception favors long-haired girls into seeming more girly.” Joshua Morancie, 17, from Brighton High, thinks presenting hair in a fashionable way identifies one’s looks more than how long it is. “It’s how they groom it,” Morancie says. Karnuah says there’s too much emphasis put on locks these days. “I think it is ridiculous,” he says, “to go out with someone based on the length or style of their hair.”

Eighteen-year-old Nathaniel Budwah, from Dorchester, prefers Rugby over Polo. “What’s more unique about Rugby is the bright colors that stand out,” said Budwah. While both Polo and Rugby once competed for customers under the Ralph Lauren label, he company announced that it was ending the Rugby line this year. Rugby clothing is still available online at places like eBay. Rugby was considered the edgier shirt, often marked by skull and crossbones; Polo more upscale and preppy, identified by a man on a horse. “Rugby is out of business,” lamented 17-yearold Stephan Durrant, of Dorchester. Jalisa Long, 18, knows a trend when she sees one -- even one that has reached the end of the line. “Popularity is not everything, but popularity is fashion and where you get it from,” says Long, who attends Jeremiah E. Burke High School. “For teens, it’s all about dressing cute, either for school, work, or going to parties with your friends.”

Zusex Romero, 17, of Boston Community Leadership Academy, has advice for teens who are not comfortable living with their stepparents: “Don’t worry. You can leave when you are 18. But to look at the positive side, they are not mean because they took you into their home to raise you and provide what you need as a young adult.” These days, an increasing number of teens are finding themselves living with a stepmother or stepfather. Often, conflicts ensue. Sara Mendez, 17, from BCLA, says her parents are together. Still, she sees the value of having a stepparent step in. “I think it’s good to have them if one of the parents is missing,” says Mendez, “because the children might find support…or look upon them as role models.”