The preparation for the half marathon includes training at different intensity and distance, tempo run fartlek and speed workout once a week, speed exercises are designed to help you move faster, if you are on of the experienced runners: individuals who compete regularly in 5K, 10K.
Your reps need to be run at speeds that are faster than race pace. You will run them over a short distance, have a rest and then go again. You will do this several times over. By getting your body used to running at this faster pace, your race pace will feel easy when the gun goes off and so you will be able to increase the pace as the race goes on or even start more quickly.
To get ready for this type of training the advice is to take a light snack 3 hours before starting and add 2 or 3 tablets of creatine 1g during the carbohydrate-rich snack.
Drink water with high mineral content, especially now that it starts to get hot, you need to be well hydrated before training and eventually bring a bottle of water, to take a sip between the reps.