English is a vast language and just like any other language it has some primary rules. For one thing, English has a grammar and spelling. You need to follow these I order to make sentences that actually sound good and are able to make sense. The spelling is just as important as using the correct tense. Then comes the vocabulary.
As you delve deeper into a language you come to realize the many words that make up the lexicon. You then start to understand how different words are put together to make coherent sentences. In the end, once you have got all this right, you are able to organize or reorganize words into sentences easily.