It happened a lot with me initially, I didn't go for job a long time, now it's okay sometimes I stutter during a job interview. Initially you can start alone in front of the mirror, keeping a check on your breath. Keep calm, don't feel bad if you stutter. Take a pause take breath then again speak slowly. Remember - Calmness and Practice is the key ! Once you're able to speak freely infront of the mirror, start recording on your phone, it helped me to build confidence. After sometime when you talk to your close friends, control your stammer by keeping a check on your breath. Communication with close friends is important. Keep expressing your interests and ideas, etc. Slowly you will be perfect and confident for job interviews ! All the best !