For parents of minor children, arguably the most important clause in your will (and the most compelling reason for you to actually get a will) is naming a guardian for your minor children. In the absence of a will, the Public Guardian may choose to be involved in the selection process and their determination of who is best to care for your children may not be the same as yours.
Many people choose a family member, believing that person will raise their children in the manner closest to what they themselves would do. Close friends are also good options. It is always worth noting, however, that a person named as guardian can always turn down the honour so it is important to have that conversation with the named guardians and ensure they are onboard with the responsibility and with your preferences for how your children will be raised.
A majority of people choose their spouse and/or co-parent as the guardian of their children. This is generally what will happen by operation of law anyway, however if you have a blended family it is even more important to make your wishes known through your will. If all of your children have the same parents, you may choose to have that same person as both executor of your estate and guardian of your children.
Many people also choose to name the same person as guardian as they do for executor if their spouse or co-parent is not able to act. This is fine, particularly if this is the person you trust the most outside of your spouse, but do note that it is the executor who will be managing your assets for your children and therefore determining the payments that are appropriate to be made to the guardian. For this reason, many people may prefer to name two different people as executor and guardian.
Naming a guardian for your minor children is a huge decision and one that should not be taken lightly. It is a difficult conversation, but a necessary one and once it is made, and your will is signed and effective, you can rest easy knowing your well thought out wishes will be known and respected.