Do you remember the time when you first started learning to drive. You had to drive with all your focus and attention during driving and any small interruption or disturbance like someone talking etc. would irritate you as it hindered the process of concentrating on your task.
But after few months or years you can drive so well and do a lot of activities during your driving. You can listen to music, talk to fellow passengers, also talk on phone (although not recommended).
Similarly if you are cooking regularly you can do that while talking and watching TV without making any mistake.
Look at a kid who is learning to tie his shoe laces. He takes both the strands in his hands, very carefully crosses them over and tries again and again and again. After a few months he can tie this knot while watching TV and without conciously putting a concentrated effort.
Why does this happen?
Well the fact is when you do something over and over and over again you just not become very good at it but this creates neural pathway in brain memory and doing it for a longer time requires less energy and concentration on your brain’s part.
It is like a neural memory that gets stronger over time. Every repetition of the task requires less energy than the earlier one. And so you are able to perform that task easily, swiftly and accurately.
Your brain develops this path for that activity and whenever you want to repeat, it can easily run through this path because it has done it so many times in the past. Try to do just the opposite or different of what you have been doing for years. It will be very difficult.
So the Thumb Rule to get better at anything is to do that thing over and over and over again. To repeat it so many times that you not only become so good on that task but can also do it easily and accurately.
This principle applies to everything in this world. You can select that particular activity/talent that you want to become better at and follow this principle.