Unlike academic essays or highly technical magazine writing, the language of the internet is very conversational. You need to keep in mind that your readers are a mix of both professional who are well versed in what you're writing about, and beginners who know nothing about the subject matter. As a rule of the thumb, plain, conversational language is always safer compared to text that's filled with jargon.
Of course, if you must use technical terms to refer to a scientific process or a car part, do so. However, you must use these to a minimum. You can impress your readers with your technical knowledge without being such a painful read. Remember, you're informing and teaching them with your articles. If the text is not accessible, and only a handful can understand it, you've failed as a web content writer.
Smooth keyword usage
Unlike magazine or academic writing, essay writing online will require you to use certain keywords of strings of keywords a number of times within the article. You need to be very artful when you insert these keywords within your text. The keyword use shouldn't only be grammatically correct. It should be "natural" as well.
You don't really need to worry about it because keywords are used to better catalogue the article in search engines online. Making them fit right into your articles should be a breeze because these keywords are also most likely the main topics of your articles.
Organized and informative writing
One of the biggest mistakes of beginner web content writers is that they think that since it's just for the web, it can be less informative or less organized than articles on print. If you have any journalistic experience or training, then you know how big a no-no it is to include fluff in your articles. This same point is true in web content writing. When you insert too many fluffy sentences without your web content, it just means one thing: you're trying to fill up space which your lack of knowledge cannot.
Never make the mistake of underestimating your readers. Your readers may be beginners, but most of them are professionals who are looking for high quality, informative articles online. If you can't give them meat in your articles, they'll leave the website and never come back again.
Also, you shouldn't mix up ideas within your web content. As much as possible, you should stick to one main idea at a time when composing your paragraphs. Always begin your articles with the gist as the lead, then expound on each point one by one. Your points should be separated with helpful subtitles so that your readers are aided when they scan your articles.
Online readers are always in a hurry, and they don't like plowing through chunks of useless text. Separating your points not only makes it easier for the online readers' eyes. It also lets them save time when they're trying to look for very specific information on a broad subject matter.