As others have already said, the relationship your child and teacher have, is a direct reflection of your attitude and relationship with your child's teacher. Stay in communication with the teacher and child and just make sure you are up to speed with what is happening in your child's education
IF you are asking this because your child is having a problem, the answer is highly dependent on the type of problem AND the child's age and more information is really necessary. In this case, I can offer up one generic suggestion which will help your children in general in life anyway. As your kids get a little older, say 9 or 10? but especially by the time they are teens - Teach your kids how to productively advocate for themselves. This doesn't mean you shouldn't step in and help, but many challenges for kids arise because they think they are helpless to do anything for themselves.
For example, I once had a student that was Really upset when she went home with a 98% on a test. She hadn't expressed to me how upset she felt about it. Apparently, it was her first time EVER answering a question wrong on any test, and she really wanted me to change the score. Her parents actually called and set up an appointment with me (through the receptionist) and did not say what the appointment was about - of course I was completely baffled. The parents did not know me well either or they may have handled this one differently as well.
When they arrived and said she was upset and wondering if she could retake the test of course I didn't just offer to change the score and Test retakes weren't allowed, but I was sorry they had wasted so much of our time with such a formal meeting. Had the girl just come to me straight away, I would have done exactly what I did do which was to look over her grade sheet with her and show her how all her scores averaged out and extrapolated out what this ONE question meant for her overall grade mathematically. When she realized it wasn't that big a deal she was fine. She also learned that I was happy to help her work in extra credit projects and other types of options if she Should Start to Struggle. All she needed do was ask.
This was the most extreme example of times when a child did not feel empowered just to come to me herself. Usually by the end of the school year, and certainly two years later by eighth grade (approx. 12 years) they were over this, it was usually the ones coming straight from primary that mostly struggled. This situation was with a young girl that had transferred in mid-year and was in the midst of adjusting to the new school, but you can avoid similar situations and stressors for your child in the first place by teaching them two skills at home.
"I messages" - because it helps keep the other person desirous of helping, and compromise.
Help them use "I messages" where they can approach any teacher, parent or even administrator and say, "I need" or "I want" and then negotiate for a win-win resolution. If you practice this skill with them at home in regard to general household management, they will learn how to do it and be able to apply it to the school environment when the time comes.
Of course they will also need help knowing when it is an issue they can handle on their own and when they will need your help, but if you are staying apprised of your child's progress and communicating with both your child and his/her teachers you will be in a position to help if your help is needed.
If you ARE having a problem, set up a meeting. Teachers are there to help.