For divorce cases that involve dividing property you will want to put together a list of what you and your spouse have, and what it is worth. Do not worry about whose name is on the title, as that does not usually matter in family court. You can lump together small stuff in the house, furniture, etc., but everything else, bank accounts, vehicles, retirement accounts should be listed individually.
For values, go with what you could sell it for. For houses and other real estate, you can go with the tax assessed value, but keep in mind that is typically low. I generally recommend getting an appraisal for real estate. For vehicles, you can enter your vehicle’s mileage and specs and get a blue book value online. There are different book values to choose from, go with private party retail, for what you could sell to another private party. You also need to select the condition of your car; your options range from excellent to poor. Most cars are in fair condition, some in good, a few poor or excellent. Be honest about your car, unless you are meticulous about upkeep it will not be in excellent condition, and most cars are not in good condition, time, wear and tear, kids, dogs all take their toll.
When valuing furniture, electronics, and other miscellaneous items their private sale value is low, these items lose a lot of value after they are purchased new; what you can sell it for now is far less than what you paid for it. There are very few personal property items that retain their value well; guns, some antiques, some classic cars, if your stuff is not in one of those categories, it is probably not worth much.
If spousal support (formerly known as alimony) or child support is on the table, you will need to be able to document your income and have a budget showing your monthly bills. Budgeting is tough, people often miss irregular items, car repair, home repair, medical bills not covered by insurance, savings for a new car if your car is old, retirement savings, do not forget these items.
If custody is on the table, know why you should get what you want for custody, and make sure that your lawyer knows too. Know the strengths and weaknesses of the other side, and your own strengths and weaknesses as well.
Good mediation prep takes a lot of work, but doing it gives you a better chance of a good result.