You are absolutely correct about a good morning routine helping your child get ready for school. In the evening, pick out the next day's school clothes with your child and pack and place his book bag by the door. Set an alarm clock to give sufficient time for dressing. Have a scheduled time for a family breakfast to get the day started together. Be sure to enlist other family members' help in caring for the newborn and preparing breakfast. Most important of all, leave enough time after breakfast to cuddle your child and read a story together before he must leave for school.
Keep in mind that your kindergartner is faced with two very stressful events: starting school and the birth of a new sibling. It may help to reduce some of the stress by talking with both of your school-aged children about the day's activities. Find out what was fun, what was good, what the teachers said, and what the other children did. Be sure to keep these conversations very positive so your younger child will see all the good things about school.
It is possible that your child may not be ready for kindergarten. Is he one of the youngest in the class? Does he adjust well to your absence? Consider your child's social, emotional, physical, and mental development in evaluating his readiness for kindergarten. Discuss this issue with the teacher.