Well, start by choosing a point of view. Will it be from the captain's perspective, a lowly sailor, or maybe an observer on a nearby island? Once you've decided that, start building the world around the ship. Consider the political situation of the time, as it often affected the actions of ships of the line. For example, if there was a war going on, the ship might be on a mission to disrupt enemy supply lines. Then, start writing the opening scene, something that grabs the reader's attention, like a sudden storm or a surprise attack.
Practice writing regularly. You can start a journal or write short essays on different topics. Also, don't be afraid to make mistakes as they are part of the learning process.
Read a lot. Reading different types of English texts, like novels, newspapers, and academic papers, exposes you to various writing styles and vocabulary.
One way to improve English writing skills is to read a lot. Reading different kinds of texts, such as novels, newspapers, and academic articles, exposes you to various writing styles, vocabulary, and grammar structures. You can then learn from these and incorporate what you've learned into your own writing.