I am blood type a and my wife is o, what can we do to prevent the ABO hemolysis of our baby?

Avoid trauma. The human reproductive system was designed to function properly despite challenges--so likely there will be no issue, except possibly right at delivery, but uncommon. If you are an "a", could be aa or ao, and mom must be "oo" to be type o, so have 50% chance baby will be type o, and non-issue. Talk to your OB to allay concerns.
See below. The chances of this occurring are very small. The treatment is the use of the bilirubin lights in the immediate delivery period (for a few days at the most. There is no reliable prevention.

Related Questions

My blood type is a and my wife is o, how can we prevent the ABO hemolysis of our baby?

You can't. Most of the time, there is no problem. Regardless, there is no active intervention that can prevent the problem. If there is a concern, it is possible to monitor and even treat, if necessary, but not prevent. Read more...
See below. This very rarely occurs in pregnancies. It can occur with your blood type but it is usually minor and can be treated with phototherapy. There is nothing that you can do to prevent it, but be vigilant. Read more...