Here's a method I've used for all my negotiations (business and personal):
Make a table with four columns: Item (what is the point being negotiated, eg, Visitation days, the house, the cars, etc); My position (starting negotiation position); Other Position (where they are) and Final position.
Then, in each row, you list your Items with one items per row. Make these as specific as possible, not broad categories. For example: break visitation up into Custody % (50/50, Every other weekend, etc), What days (weekends, rotating schedule, etc).
At the beginning of the meeting give the other side a copy so you can both work through it. Leave space for additional topics the other party might bring up, or other topics you didn't think about.
[On a separate version - one that you don't let the other side see (keep it at home, in your bag, etc.) in the "Final" column, put down what your absolute lowest agreement would be. Example: You have 50/50 custody. Any less than that, you can't agree. (A judge might order that, but that's not the negotiation). This helps you know in your head what you want/would agree to and you can refer to it after the meeting)]
Leave lots of room in each "box" so you can jot notes of positions during the negotiation of the day. Where did you move to, where did he move to.
If you come to an agreement, great, note that in the End position column (and what it was). If you don't - highlight what position you moved to and where he moved to. You can come back to this later at later negotiations.
At the end of the meeting, review the positions with the other side - what you agreed to, what you didnt (and what each side's position is for that topic).
After the meeting, retype your table with updated My Position/Others Position (with where you each ended) and Final position for those that have them. Send a copy to the counter party (be sure to note at the top of the document that this is a summary of negotiated positions, and are subject to change during further negotiations).
What this does is a few things:
1) Helps you figure out what you want. What is important to you and what is not. What are you willing to trade to get something that is important. If you don't care about the china/silverware, but want the better car, offer one for the other.
2) In the meeting, it keeps you focused on one topic at a time - no jumping around. If the other party tries to jump to something else, say "We are talking about X. We can talk about Y later, after we conclude talking about X." It's a classic strategy to knock the other party off balance by jumping all around different points in the negotiations.
3) You can quickly come to agreement on some topics and get them out of the way. This is also a psychological trick in negotiations: build momentum by "stacking" your topics from easiest to hardest. By quickly banging through the easy ones, the discussion builds a momentum of getting to "yes." You'd be shocked how after 20 min of "yes" you find yourself - and them - finding common ground on the stickier subjects, because you are both used to agreeing.
4) Records your positions. By reviewing it at the end of the meeting (and make sure you do), you reaffirm that you've come to agreement on positions. It will be very hard for the other side to say later, "No, we didn't agree to that," if you get confirmation that they did. Also why you send a copy of your cleaned up notes.
5) The cleaned up notes for a starting point for future negotiations. You shouldn't go back over things you already agreed to. If the other side brings those up, you just say, "We've already come to agreement on that. Let's move on to the still open issues." Of course, you CAN open up closed things, but that's going to cost the other side - never give something without getting something in return.
6) If you are dealing with a difficult person (ex), the document shows a good faith effort on your part at negotiations. If they come back demanding everything all over again, it can show a court that the other side is negotiation in bad faith (judges don't like this)
NB: With some people negotiations are pointless. It is easier and simpler just to go to the judge because the other side is just going to be unreasonable. If you KNOW your ex is going to be like this, save the time/money of it and go to court. Some places mandate mediation so you have to go through it for nothing else but to demonstrate #6 above.