Double check your thoughts if they lead to misery!!
Prevent going deep inside continuously for a long time.

We cannot keep thinking stuff. Become a doer not an imaginer. Execute what you already know, absorb from outside and respond appropriately.
People like me think a lot. I tend to internalize and learn new concepts as much as I can on everyday basis. But the psychology of things keeps me pre-occupied. The result of this overthinking prevents me to break free from the cycle of procrastination and untimely results according to the goals I pre planned. Learning is one goal, but timely effort gets dwindled in the process if I only think than really do. I have passed many sleepless nights thinking, causing unnecessary stress.
Child development requires all possible effort by parents and teachers to make them internalize values, morals, facts, and capacity to learn life-long.
But as an adult, we do not internalize easily, we critically assess if the information is right. What is taken literally, or by hearing, observation and discussions, is still not enough, we simply do not want to go against our belief system. When we are intrigued, we are bound to think. That makes us intelligent. Largely, it is OK to think, but do not keep repeating and analyzing your actions and reactions throughout the day. Our mind needs rest. We need to disconnect. We need other work, some fun and endurance.
Even if we think good things, it can lead us to misery, because thoughts do not reach accomplishments. It is like a patient with cancer. Everyday we are battling the same pattern of malignant thoughts. It disturbs. It hampers productivity of all sorts. It prevents us from following a routine. We internalize thoughts and actions so much that we become slaves to our mind, and there is no way out but to think for a very long time, keep strategizing and mess up with good things in life including our presence of mind.
What can be done is solve the problem by jotting down 5 thoughts everyday that keep you pre-occupied. Do so repeatedly. In the beginning the mind resists because thinkers’ mind loves to think, its a very permanent habit. To get over it, initially write down these thoughts frequently and solve the problem again and again, it could be the same solution. One fine day, the thinking lessens. The trauma reduces and you become comfortable with yourself. Double check if your thinking starts every 5 minutes and does not allow you to do work, study or enjoy with others. You have to curb it. Solve the problem. Only you can do it.
If the decisions are hard, one thinks frequently. The mind keeps on doing it for the sake of it. It is a mind in prison that wants to break-free. So recognize your thoughts. Its hard to dismiss something that comes automatically. So you need to do something. An action is required.
For me, I write, read, sleep, exercise, teach and learn. I assimilate knowledge and apply. I have reduced the thinking addiction and shall keep on doing it until I succeed. Keeping busy makes me less miserable. But I still have those every 5–10 minutes thoughts, that are nothing but repetition of day’s errands and what I derive from them. To a limit, it begets success. To a limit, it improves our intellectual capacity. But keep such patterns in the early evening when you return home from work, for a maximum for 1–2 hours. We can give this introspection and internalization importance by keeping a confidante with whom you can discuss the day, and so it finishes, the problem solved with just one phone call or evening tea with a friend.
There is one another way, read scriptures with their meaning, for hours until you quieten your thoughts running in the back of your mind. Then do the necessary work. The time it took you was 5 hours of unproductivity. But by reading scriptures you forcefully shut the inner jargon. Then you trick your brain this way to enjoy the goals and work you set out to accomplish in a matter of just 1 hour. The rest of the time you spent working hard on scriptures.
Movement and keeping busy is an answer to most of us thinkers. Think work and do the work, to prevent falling for your thoughts, and manage them appropriately.
Become a great thinker by allocating not more than an hour or two for introspection, the rest of the day needs action only.