Create a Private Asset Trust (or more than one trust) and make sure to transfer the assets. That means a Deed for each real estate property, and other transfer documents like bank account signature cards, and Transfer Agreement for Coin Collections, guns, stock, and business assets.
Create a personal will. This will cover any untransferred items intended to be managed by the trust, and could also handle unexpected assets that were not covered in the trust. An example of a surprise asset for the will to handle is an inheritance, a damage award, or a gift received after the trust was last modified.
Treat those with the same degree of relationship to you equally (such as "three children get one-third of the estate, equally, and undivided"). Families fight over inequities and feelings get hurt. Don't create problems.
Be Descriptive and Very Specific
Be specific with bequests. Decide exactly who will get what; leaving the decisions to heirs provides fodder for infighting.
Loans and Debts
Make provisions for loans. If you've made a loan to a child, make provisions for whether the debt will be forgiven or must be taken out of their share upon your death. If you owe a family member, be sure to disclose it and make resolutions regarding allocations. If you have debt to others, or mortgages, or car loans, make a payment plan from assets, and describe the solutions.
Don't try to pass a business on through your will. There could be a complete halt, or serious disruption that could destroy your business. Even if you have just one child who will inherit the family business, you risk other children who may not like that decision. Transfer the business (or the equity) into a Private Asset Trust to eliminate attacks. You can even make installment sales to a manager or family member (or a combination of people) that will pay your estate and finalize continuation of the business, without interruption.
Give Only What You Own
Be sure you own what you give. If you have joint ownership in a property, you cannot leave it to an heir - it will go to the joint owner.
Get Your Own Estate Planner
If you're in a second (or more) marriage and have children from different marriages, get your own estate planning attorney. Children of the first marriage may raise issues if you and your second spouse have the same lawyer.
If you anticipate problems, get a corporate trustee or executor. A professional trustee or corporate executor may be more expensive, but could help eliminate family fights if those are anticipated over your estate. At the worst, family members can be mad at the professional, allowing the family to be united in their resolution, instead of destroying relationships.
Prove Your Mental Health
Establish your sound mental state. One of the most common legal challenges to a will is that the testator was not of sound mind. Consider being evaluated by a doctor and/or a geriatric psychiatrist prior to signing your estate planning documents.
Add a No-Contest Clause
Adding a no-contest clause to you will means that any beneficiary who contests the validity or any provision of the will forfeits his or her interest. This is often a highly effective way to stop a fight before it starts.
Detail any Disinheritances
If you plan to disinherit someone, make it clear that it is intentional but don't give a reason that could be challenged.