Stay hydrated
Eat a balanced diet with enough calories
Include zinc-rich foods
Include omega-3 fats
Get enough sleep
Exercise regularly, but avoid overtraining
Reduce stress
Avoid smoking
Limit alcohol
Avoid recreational drugs
Maintain a healthy weight
Avoid long periods of heat exposure to the groin
Ejaculate less often if you want a larger volume per release
Consider seeing a doctor if volume is suddenly low or you have pain, blood, or fertility concerns