Making co-parenting work is something that requires you to put in an effort. You and your ex will have to decide to work together for the good of the children so that they can thrive. You can't focus on the adults in the picture because this can lead to your making decisions based on past hurts.
Remember the reasons you are co-parenting. Children can feel more secure and will be able to handle problem-solving better with a positive model from their parents. They can benefit from the consistency and the good examples you demonstrate. Keeping these points in mind might help as you work through conflicts that creep up.
Decide on communication rules
Communicating with your ex can be one of the biggest frustrations. You have to set rules from the get go so that everyone knows what to expect. The most important thing is to demand and give respect. This has to be present when you are around your child and when you are alone with your ex. It can be difficult, but it sets a good precedent and shows your children that mutual respect is always a priority, even when you don't get along.
If you choose to communicate via written methods, remember that your emotions and intent might not show through. Think about how things might be perceived when you write them. It might help to write out what you want to say and walk away for a bit and then review it before you send the message.
Flexibility is a big requirement for these situations. You might not be able to keep things exactly the same all the time. When you or your ex has to make changes to the schedule or the way things are done, be willing to make changes if they are in the child's best interests.
Of course, consistency is important when you co-parent. Once you set rules that are supposed to span both homes, try to keep them in place. As the child grows up and matures, changes might have to be made. This should only be done through teamwork with your ex since you are co-parenting.
You need to ensure that your parenting plan outlines the basics of how the relationship will work. This gives you something to turn to when tensions and difficulties arise.