Both during a specific race — by working out a race plan and following it — and by thinking long-term. Racing to your full potential is unlikely to appear suddenly. Consider not only the pace of your next race, but races one, three or even five years down the road. Set yourself a goal for the year (new distance, new PB) and work steadily towards it.
Race-day emotion and adrenaline can easily override judgement, especially early on in a race. Divide your race into sections and monitor your effort so that you build, rather than lose, momentum over the race as a whole.
When the going gets tough, dig in. Talk yourself into keeping going. The trick is not pushing too hard, too early. There’s a moment of truth in every race when you really dig deep, but you don’t want to face it too soon. Ideally you want to put it off until you can visualise pushing strongly through the last stretch — whether that’s 200m or a mile — without anything being able to hold you back.