Hi,
risk for type 2 diabetes is partly genetic, but with a great and large environmental impact . The most important things you can do are those that reduce insulin resistance / insulin levels / blood sugar levels. These are:-
1. Eat low-carb, moderate protein, and fat to appetite. Low carb, if you are seriously at risk, may be as little as 30g /day, though many may find that 50 - 100g /day is still ok.
2. Normalise body weight.
3. Exercise daily.
4. Buy a blood glucose meter. Check your blood sugar 2 hours after eating. Your blood sugar should ideally be < 120, and even better if it is < 95. If it is not, then you need to adjust what you're eating to achieve this (reduce carbs!)