Welcome to the forum, did they tell you your HbA1c score or give you any meds?
To prevent progression the obvious bit is avoiding the sweet stuff. The less obvious bit is avoiding large portions of carbs in a meal.
Carbs like cereals, bread, potatoes, pasta, rice etc etc get broken down to sugars so larger amounts of carbs can impact blood sugars even for prediabetic people. Many folks here aim for 130 or less carbs to aid control of prediabetes or type 2 diabetes.
Excess weight (in particular around the tummy) can lead to insulin resistance. They say your waist measurement should be half your height, eg if 160cm high then your waist should be 80cm around.
If you do have weight around the tummy, the good news is that many people reducing carbs find it helps weight loss.