The rising mountain of student debt, recently closing in on $1.2 trillion, is forcing some entrepreneurs to abandon startup dreams and others, including Christine Carney of Orono, Maine, to radically reshape their business plans.

Ms. Carney, 29 years old, and her husband, John, 31, started Thick & Thin Designs, making and selling food picks in the shapes of zombies, bikes and deer antlers after a brainstorming session while she was cooking dinner. The couple, both students at the University of Maine, where he is earning...