As far as planning is concerned you will have to go way back in the past. Even then the planning word was popular. They also used to plan for their children so that nothing harms them. However the thinking has change from that period. People now plan in far better way than those days. Estate planning is also very common. However, there are some mistakes which every one makes. The first mistake which is the most popular is that you do not even try to plan and end up without planning.

There are many other mistakes. I would like to list some for you. They are as follows:

1. Improper use of jointly held properties is really a big problem. You might have done it for some reasons but your ancestors will find it very difficult to handle. Hence you should make some clause in the agreement about how to over come this obstacle.
2. You might not use the life insurance policy to a good extent. If the primary beneficiaries of the life insurance policy are deceased and you have not named any secondary beneficiary then this might create a problem a problem. If your children are minors and you have not designated anybody at all then getting the insurance money will really be very tough.
3. Lack of liquidity is another point. The people might have problem to manage money for death tax and other final expenses which are really very important.
4. You might choose the wrong executor. What is the guaranty that the person whom you are choosing as an executor will be fair enough. You cannot say that there can not be any conflict as far as interest is concerned.
5. Will is another problem which you might face. More often than not the will remains unnoticed. They only come in limelight when you are married, divorced or have children. You must keep in mind that wrong Will end up as the estate in wrong hands.
6. You should make sure that you should not pass all the property to your spouse who then passes it to your children. This is basically due to interest and tax concern.
7. You cannot really pass such a great sum of money to a 20 year children who take life as a fun. You should make some assumptions that the property will only be passed to him when he crosses some particular age limit.

There are many things apart from these all which you should really keep in mind. If you will not keep them in mind then you will definitely loose the chance of making proper arrangement regarding the property. Hence make sure that you go for proper estate planning.