Hi @sameeshsmn, learn about On-Page SEO mate. I'll divide this into two:
Regarding the Text content, you need to finalize a Focus Keyword for your article. If you have installed Yoast SEO plugin, this will be very easy to follow. Now, after that, pick 4-5 keywords related to your focus keyword. Say, if your focus keyword is "iPhone Accessories," then you can also use keywords like "iPhone 7 Plus Accessories", or even "Best iPhone Accessories." You can also expand it like "iPhone Accessories for Photography" and "iPhone Travel Accessories." I would suggest you use them naturally in your article and also consider the optimum keyword density as well. Now, learn about internal linking, take Wikipedia for inspiration and interlink your existing articles. That's all. Rest all depends on your writing skills. Prepare a quality article. Increase comments and social shares.
Now, we need to focus on Images, because they are often underrated and avoided by several, but they don't understand the potential traffic they can get from Pinterest and Google Image Search. So optimize your images by using quality HD images, make sure you compress them using any optimization plugins (like WP Smush). Use proper keyword-based alt and title tags.
These are more than enough for the time-being, but always remember, no SEO can replace a good quality article, so write well and do these later! Best wishes.