There are general rules to follow, but you should always defer to the expectations of each site you're writing for, aka the target audience. An academic audience has different expectations than sports fans. Cater to the site's audience to increase the chances of being published.  Make your writing brief. Writing on the internet is intended for a mass audience, and long pieces are generally not desired. Websites want articles ranging from a few hundred words to 1,000 words max. If you are a long-winded writer, break this habit. Write concisely. Spectacular introductions. Journalists say you need a good lead. The general public has a short attention span, so you need to grab people from the very beginning if you want them to continue reading. Regardless of the topic you're writing, hook the reader with a spectacular first sentence. Keep readers wanting to continue reading the entire article. Break writing up with bullet and number points. Large blocks of text cause readers to lose interest. Break text up with bullet points or subheadings. This is appealing to the reader's eye and keeps your audience interested. The best way to expose your writing to others is by starting a blog. This will demonstrate your writing skills and proves you are capable of producing content that websites and companies desire.  Make sure your blog covers the topic that you would like to write about professionally. For example, if you want to be a movie reviewer, you wouldn't start a blog about cooking. You need to show potential clients that you have expertise in a given field. Proofread your blog carefully. Your blog shouldn't be sloppy. Remember, you are presenting your writing to the world. Make sure it is neat, clear and, especially, grammatically correct or else you could hurt your chances of getting work. Your blog could also be a way to make money. If you have a lot of followers, companies may approach you to advertise on your blog. This is another motivation to make your blog as good as possible. Like writing a blog, having an...

TL;DR in Indonesian:
Sesuaikan tulisan Anda untuk setiap situs. Buatlah blog. Jaringlah pengikut di media sosial. Bergabunglah ke situs yang menawarkan pekerjaan sebagai penulis lepas.