1. Don't try to be friends too soon.
Your reactions, impulses, needs and interests will cycle differently. You need a safe, professional distance from each other to conduct the business, set the rules and boundaries that will allow you to move into a parenting partnership and to see if a new friendship might flourish.
2. Lawyers prepare for the worst. Mediators bring out your best.
Start with a great mediator who is also a lawyer. If you're not at war already, heading to a sharky lawyer out of fear will certainly start one. If you have a working relationship, similar goals and no huge wedge issues up front, try an experienced mediator first. You'll save oodles of money and are more likely to come out of it with the good parts of your relationship intact
3. Write a Parenting Plan that speaks directly to your children.
If you start out with "To Adam and Ella," you are more likely to write a plan with your kids' best interests in clear focus. Picture them reading it. If they are old enough, share it with them. Show them you are working as a team, from the beginning, on their behalf.
4. Trust But Verify: Write everything down
Do not assume either of you will remember or abide by the agreement no matter how friendly things are. Get it all in writing in a coherent plan and agreement so nobody 'forgets' or acts out. This is why a mediator who is also a lawyer is such a strong choice. Especially with issues of money and parenting, the more details are in writing the better. For example, if you live in the same area and are comfortable with the non-custodial spouse or co-parent visiting during non-visiting times or if you are agreeing to a degree of flexibility, write it down.
5. Agree on how to disagree
Failure is inevitable. Things will zig when you thought they'd zag. Minefields will blow in areas you had no idea were even tender. Have a plan for that. What's your process for when you hit a snag? What if somebody gets a better job and the money changes, or if somebody wants to relocate or if you think parents should pay for graduate school but he doesn't? What is your process? Head back to mediation? Write down the precise process so everybody is clear.
6. Time Outs: Outline clear and effective consequences
.Agree on what happens if one person does not abide by the agreement or somehow does not follow through. Like with parenting, you need to know what happens to those who break the rules - make sure you know what happens to the rule breaker and what the ex gets to do about it.
7. Resist old patterns
Part of the relief of divorce is you are no longer responsible for your partner's insecurities, self hatred, wacked relationship with his/her family, professional disappointments or any other despair you had to live with. Same for them. No more front-loading onto them and no more listening TO them. You both are released so be released. Resist the urge to give or seek old patterns of support. Beware of divorce sex. I'll just leave it at that.
8. Let your relationship transform. Burn the old and see what emerges.
If your relationship is going to have any chance at re-emerging in a new, healthy form that allows you to be friends and strong parenting partners, you have to let it all go first. Who knows what you'll keep or who you will become. Don't feel betrayed if the other person withdraws or remains silent when you start a riff on how hard it is to blah blah blah. She/he is wisely trying to build new boundaries for the care and safety of your relationship. It may feel lousy and lonely for a while but it's the only way to move forward in a healthy way.
9. Get together as a (newly-reconfigured) family
If you can, make time to gather as a family. Go out for dinner. Show the kids you still care about each other. They are going to want you back together anyway and you might as well start demonstrating early that they still have two parents who love them and value each other, and we are still a family no matter what.
10. No new people
If there are third parties involved, you're probably not going to be able to take any of this advice because somebody done somebody really wrong and somebody is enraged, betrayed and deeply wounded. If, however, somehow there were others involved or others come enter the scene early on, do not, DO NOT involve them with the kids. Even if the kids are teenagers it's too confusing and raw. Let the focus be on the family of origin.