The ability to deeply concentrate on something is a skill that you can practice and train to improve.
It is not something that magically appears when inspiration or motivation strikes.
The systems you build to govern your life, your morning routine, your structure of working hours, enforcing a strict “no-internet-distractions” policy with yourself during those working hours, etc… these systems beat inspiration.
They are repeatable, they are reliable, and they don’t wait for the angel of inspiration to stir up your waters of motivation.
Don’t rely on that fickle fool in your mind who tells you of motivation. "I just need some inspiration!" "Oh, how I could use motivation!" These are seductions of your lower beast.
Instead, build systems that force you to train your mind to focus and do deep work. It's hard. It takes time and effort. Get started as soon as you can.