What you include in your will is really based on your personal situation. For example, if you are married, then the assumption is that everything you own jointly will go to your spouse. Also, the custody of your children will go to your spouse. However, if you are single, then things could be more complex. US News and World Report explains that there are certain basic considerations to make regardless of the size of your estate or your specific personal situation when writing a will.
First, you need to provide for your children. If you die, the children will go to the other parent unless there are circumstances that make that impossible. You want to plan for that type of situation. Make it clear who you want to have custody of your children if the other parent cannot take them.
You also need to decide who gets your assets. If you have assets you do not own, such as a home, then you also need to plan for what happens with that. If you are married, then your spouse will usually assume responsibility for anything you own jointly. If you are single, then you should assign assets as you wish.
Make sure you are specific with your instructions. Do not leave it up to the executor to make decisions. The court may take issue with that and your will court get stuck in probate for a while. This would tie up your assets, which could cause financial issues for your loved ones. This information is for education and is not legal advice.