How to Cease Negative Thinking
The best way would be to replace negative thoughts with good ones. When you concentrate on just blocking it, you are in fact reinforcing or furthering the negativity. Negativity begets negativity. If you can make light of them, all power to you! If not, just try shrugging it off and direct your concentration only on the positive thoughts, actions and images.
Keep this saying in mind: There is a good thing in every bad thing that happens.
Practice good thoughts often and it will become easier in due course. Start by appreciating being alive for example, each breath of air you inhale, the five senses, happy sounds, the food you eat, loved ones, family and friends. Be grateful for good health and the absence of serious pain, recount your favourite hobbies, and meditate on the beauty of nature expressed by all living creatures, objects and places. Be generous in your charitable acts and deeds. When you come upon another being lavish unstinting compliments and praises on them. Each time you focus on good things and inwardly give thanks, that feeling of contentment reenergizes your spirit. As you plant the seedlings of joy deep within your heart your life will be transformed into a more favourable state where you shall reap with the least effort all the benefits of a bountiful harvest of peace, good health, joy and prosperity.