This issue will start by telling you about the most important step to productivity. Then we will look at how to follow that step and after that, we will see a few tools that can help us in this.
Since this newsletter will be focusing on improving ourselves, we will start by improving our productivity. Being more productive can help us achieve many of our goals.
To work on our productivity, we will start with defining productivity. On googling it, this is the definition I found:
A productivity measure is expressed as the ratio of an aggregate output to a single input or an aggregate input used in a production process, i.e. output per unit of input, typically over a specific period of time. 
According to the definition, we can be more productive by either producing more output (keeping our input efforts the same) or by reducing the input efforts while achieving the same results .
How can we do that?
We can achieve greater output with less effort if we do our tasks with better focus. Better focus means that we can direct all our energy towards achieving that particular goal, rather than wasting some of that energy on useless tasks.
This means that we can achieve higher productivity if we are more focused. How to get more focused then?
We can achieve better focus by removing distractions from our lives. Distractions are all those events that make us leave the task at hand and switch to attending that event. To get more productive, one has to spend a long duration of time on a single task without getting distracted .
Now how to achieve better focus with fewer distractions?
Consistency makes the entry here. Our brain is a highly plastic muscle. This means that we can shape our brains into any form that we want (figuratively) quite easily. It is similar to training our biceps in a gym. The more you train, the stronger your biceps grow. The more you practice being less distracted, the more focused your brain becomes.
You become good at whatever you practice.
This is why you are less focused now. In the pre-smartphone era, you were able to study for long hours, could solve tough mathematical equations without breaking a sweat. But now you suffer from a high amount of distractions all the time such that being distracted has become a habit.
To counter this, make a habit of not getting distracted. Allot a time and space for deep work and do not let yourself get distracted for that period of time. Start small and do it consistently. If you keep doing it for long enough, you will start noticing the positive effects of this very soon. You will be more focused at work and feel more productive. To know about my experience with this experiment, you can check out this answer on Quora.
Coming to the tools of the toolkit, I would first recommend you to read the bestseller Atomic Habits by James Clear. The book presents actionable tips for the reader to build better habits (or stop bad ones). This is a great tool if you want to learn how to improve yourself because you are defined by the actions you do every day, which are your habits.
To help you with consistency, there are some great habit trackers available. Forest gamifies habit-building using trees (you can plant real trees too!).
Engross is not a habit tracker but a Pomodoro timer with a unique concept of Hit me when you are distracted button. This lets you identify when you are distracted and act on it.
Both of these apps also allow you to block app usage on your smartphone.
 Source of the definition of productivity, from Wikipedia.
 I couldn’t help but think of this.
 Deep work is defined in greater detail in Cal Newport’s book Deep Work.