In the eighteenth century, it was usual to write long sentences. Writers would develop an idea within a sentence that could sometimes take up as much as a page.

You are not writing in the eighteenth century now. Attention spans get shorter by the day with texting and video to contend with. Make your sentences no longer than necessary to get you point across.

Nowadays, an excessively long sentence is usually an indication of poor written english. Occasionally, of course, it may be desirable to throw in a long sentence or two to add variety and to break up the pace and rhythm of your article. But never let a sentence get out of control. Always make sure that you can understand it and that you have it on a tight rein. You should not let it run around uncontrolled so that it ties itself in knots.

The purpose of your sentence is to communicate an idea. Listen to your friends in conversation. They understand each other perfectly but do they talk in essay length sentences? I doubt if they would stay friends for long if they communicated like this.

There's always an exception to prove this kind of rule and just occasionally a complex idea requires a complex sentence structure, but such occasions are extremely rare and please don't make a habit of long sentences.

You are never writing an article to show off. You have unique knowledge in a particular area and your aim should be to help the reader by communicating your expertise to them.

If you think that writing elaborate sentences will demonstrate your prowess, then you are sorely mistaken. Nothing could encourage your reader to click away in search of a writer who is less full of himself or herself. You know your field inside out but don't stand your sentences on their head or turn them inside out. You demonstrate your knowledge best when your sentences are straightforward.

Keep your sentences short.

And always believe in yourself and write from conviction.