Article length should be 650 to 1000 words, so that you can describe about the topic very easily and properly. It should be always informative and not exceeded keywords.
Aim to write 500 words first. Get as much 'interest' in that with whatever wordsmithing abilities you could muster. If it looks likely to overrun the 500-word limit, then start a “take 2” (part 2) and carry on for another 500 words.
If your average article length is under 200 words, search engines will likely be more critical of the content, and the general rule of thumb is that articles of 300 words or more are less likely to put you at risk for infringing on “thin” content.