Get out of the way of the kick. Move sideways. Move backwards. For example, if somebody was to execute a right leg roundhouse kick towards your front leg, you could simply pull your front leg back to your back leg for a moment and move forwards again. Adding hand blocks to evasion will allow you mobility and the safety of actually blocking the technique. For example, a body front kick can be blocked with a low traditional block, similar to the first move from Iron Horse. Slipping out of the way of the kick makes the block more effective again.
As the attacker goes to deliver a kick, you place the sole of your foot against the thigh of their kicking leg. This must be delivered quickly and early in the kick’s range of motion, though can allow you to ‘shut down’ an attack completely.
Block circular kicks, such as roundhouse kicks, with your shin. If your attacker executes a right leg roundhouse to you, while you stand left leg forwards, raise your left knee upwards and push outwards. Aim to block the kick at their ankle, with the lower part of your shin. Shin-on-shin contact may be painful to begin with, though repetitive training allows progressively greater contact.