Drill for mental focusing. The data that is reaching your mind from the eyes is making it busy, sometimes disturbed. The idea is to control the mind by controlling the eyes. This drill of focusing on a point is an example for a strong drill that is directing and focusing your mind and with it, the body and the breathing.
Stand at about two and a half, three meters, from a black point with a diameter of about one inch. Relax your face muscles, relax your shoulder muscles, relax your hands. Stand straight. Focus your gaze on the point. Try not to blink, definitely do not move. Feel your breathing, be witness for your breathing
A drill like this can start with about three, four minutes. Reaching the level of 10 or 15 minutes is considered good. If you find yourself thinking of any thoughts, if suddenly you are aware that you have an internal monologue, acknowledge it and drop it. Focus back on the point, feel the breathing, do not move.
Focusing and relaxing exercise, while sitting. Just sit comfortably and straight in a chair. Focus on your breathing. Breath in, breath out. Pay attention to the process of the breathing. Especially, put attention to the points and moments that the air is changing direction, meaning from inhale to exhale, and from exhale to inhale.
Pay attention to the whole process. Try to slow it down. If you feel comfortable in stopping your breathing, it is definitely a possibility and a good drill to practice. However, definitely you should pay attention to the moments that you stop the breathing and start breathing again. Focus on the moment that you inhale, stop the inhale, then start the exhale. These moments of stopping and starting, put more attention to them.
While you do this, you can be with eyes closed, sit comfortably, and do not move your body. In the early phose of the exercising, I suggest that you pay attention to the different parts of the body. Also, feel if they are relaxed or contracted. One good way of doing it is to contract the specific area, like the muscles in the face or the shoulders or the neck and then relax them.
Automatically, you can reach a much higher level of relaxation. This contract and relax is a very efficient tool to relax your whole body from the top of your head to the toes of your legs, or from the toes of the feet to the top of your head. Breathing is done in a very relaxed manner.