Naming only permanent guardians.
Usually parents name permanent guardians for their minor children in their Wills. While this is a good thing to do, it does not fully protect your children in the event you become temporarily disabled or incapacitated. Permanent guardians named in your Will only take effect if you pass away.
Choosing enough alternates.
You should always choose at least two alternates for your temporary and permanent guardians. You never know if a named guardian will be unavailable when needed. Having alternates will prevent any delays.
Choosing a couple.
If you are thinking about selecting a couple as guardian for your minor children, ask yourself if you really want to name the couple as guardian or just one member of the couple as guardian. For example, you name your sister and her husband "jointly or the survivor." This means that if anything happens to your sister, your brother-in-law, who you may not like, will be guardian of your children. By using phrases such as "jointly or the survivor," "jointly only," or "alone" when naming a couple as guardian, you can clearly define exactly who you want acting as guardian for you minor children.
Not excluding individuals who you don't want as guardian.
If you are absolutely sure you do not want certain people acting as a guardian for your minor children, then formally exclude them in writing. It's simple to create a document naming individuals that you do not want to care for your minor children. Don't forget to get it notarized!