Step1
Unless the blood test requires avoiding water, make sure your child drinks plenty of water before the test. This will make his/her veins easier to find and minimize discomfort.
Step2
Mirror and accept your child's emotions. If he/she seems mad, say "You seem mad". Draw out whatever emotions your child feels.
Step3
Don't tell your child to "grow up" or "act like a big boy/girl". Accept whatever he/she feels. Tell your child that it is okay to feel scared or mad and that you understand.
Step4
Try to get your child as relaxed as possible before the blood draw. Play soothing music in the car, bring along a favorite toy from home, or play a fun game along the way.
Step5
If possible, take only the child who is getting the blood test along and leave siblings with a sitter.
Step6
Make sure you have plenty of time to get to the blood draw location so you won't get tense in traffic. If you get upset and anxious, so will your child.
Step7
Make friends with the lab technicians. Be friendly and treat the lab staff with respect, and they will be more likely to give you the best service
Step8
If your child gets upset during the test, give him/her options. Ask if he/she would rather take a break to calm down, or just get it over with. Make sure he/she knows that not doing it is not an option.
Step9
Focus on your child, don't worry what others at the lab may think. If your child is crying, cry along with him or her. If he/she is kicking and screaming, gently hold him/her and quietly sing a favorite lullaby into his/her ear
Step10
When the test is over, tell your child that you are proud of him/her, no matter how he/she behaved during the test. Reinforce it with a reward that you think is appropriate for your child, such as an ice cream cone, new toy, or just a small reward.
Enthusiast 
