As you continue, you write faster, you begin to trust you instincts, you begin to see places you can go, ways of tackling the subject that are eminently more satisfying than where you started. Write every day if you can.
And when you aren't writing, read. Read voraciously. See how other authors you admire handled the subjects as well. Then you learn what it is you have to offer that is uniquely yours because you begin to see the thrust of other authors' passions and perspectives. It fuels the fire and helps you write better. Read book on writing as well ... although never let those books replace writing itself. The writing is key. The writing develops and evolves over time. Enjoy the process and never stop trying to improve. Accept that early work is likely to be crap and that serious editing is always part of the process. Never deceive yourself into thinking your words are golden. Never imagine your pearls of wisdom cannot be improved. That way lies pain and disappointment. Anyone who thinks their work is perfect has lost the desire to learn and their work will suffer.
Now, stop reading and start writing. There's no time like the present.