Come close to your horse. Pat him warmly on the shoulder and lean on to him. Stroke his shoulder with one hand and make him lift his one leg with the other end. Hold up the hoof for access so that you can work on it comfortably. If you do it regularly, your horse will recognize the notion when you want it to lift his leg. It will take some time and convincing in the beginning.
Use the hoof pick to dig out all the particles caught in the hoof. Work slowly, removing all the deposit. However, you must avoid the V area of the hoof. This area has soft and sensitive skin that will be irritated due to the hoof pick and can upset the horse. Normally, this area does not hold much debris.
Drop the leg when you have cleaned the hoof. Repeat the process with all the four hooves until you are sure that your horse is totally free of any hoof build up. Cleaning is your best chance to judge the health of your horse. Check particularly for any wound or swelling that can cause problems for you. If you notice any such thing, treat it immediately because the smallest of infections can totally paralyze your beast. Clean the hooves of your horse every time you return from a ride. Do not leave any sharp objects lying in there which can develop an infection.