1)Use boneless chicken thighs for more juicy chicken kebab.
2)If you are using breast, then cook it little less.
3)Don't over cook chicken else it will get dry.
4)Marinate the chicken for atleast 2 hours or overnight for best result.
5)Bring chicken to room temperature before cooking.
6)You can marinate the chicken for upto 2 days.
7)Store marinated chicken in freezer upto a month. Thaw it in fridge overnight before cooking.