When you start writing in a serene mindset or in a state where you feel inspired to write on something which is so compelling that you feel like putting your thought process into concrete words, you’re naturally inclined to get that flow wherein you’re not conscious of how many words that you employ to express your heartfelt emotions, you just get into that mode in an effortless manner. For this to happen, you need to be well read and have had made efforts to equip yourself with varied and extensive knowledge through reading books and others means of knowledge acquisition, which enables you to improve upon your vocabulary and knowledge base so as to do a “structured thinking” which is sine quo non for any impressive writings. That is, you should not force yourself to write on something which in any case doesn’t fall in the category of impressive writing when there is an element of spontaneity is missing. When you struggle to write something then you are not a spontaneous writer, however you can keep improving upon things in the manner above stated.
As long as you show interest and inclination to write a “quality stuff” and keep striving to do the same, day in and day out, you’re bound to show improvements and get appreciation for your work.