Most estate tax planning revolves around maximizing the use of the federal and state estate tax exemptions. Ideally, good planning eliminates estate tax completely, but even if you have a very large estate, it can help to minimize how much is paid.
If, like most docs, your estate is worth less than the estate tax exemptions, there will be no estate tax due at all. You can help keep the value of your estate down by spending your money and by giving it away. You can give any amount to charity at any time, and you may even obtain some income tax benefits for doing so. However, you are only allowed to individually give $17,000 (2023 limit) per year away to anyone else before gift tax laws kick in. You can give more than that, but any amount above $17,000 per year requires you to file a gift tax return, and it starts eating into the estate tax exemption. Once it is gone, you start paying gift taxes, which is essentially the same as paying your estate taxes in advance. Keep in mind that you can give $17,000 to your child and $17,000 to your child's spouse, and your spouse can do the same. So, the two of you can give $68,000 away each year to your married children without having to hassle with the gift tax.
If an asset is likely to appreciate, it is better to give it away before it does so. That way all of that appreciation does not end up in your estate and would not be subject to estate taxes. This can be done directly, by simply giving the asset to the heir, or it can be done indirectly using irrevocable trusts, Family Limited Partnerships (FLP), or Family Limited Liability Companies (FLLC).
Roth conversions can also reduce the size of the estate since the IRS considers a pre-tax dollar and a post-tax dollar to be equivalent when assessing the size of your estate.
How to Optimize Your Estate for Inheritance Taxes