Tips/Hacks to grow organic SEO, Keywords and Ranking

Hi all, I'm new to here but I'd like to enlist all of your professional help. I'm a marketing person in a new startup and tasked to grow our SEO, keywords and rankings well. This is not my expertise, but I'm learning and hoping to know more.

Currently, my strategy has been growing our blog content with a very varied articles content (close to 200 articles on our website) but I only managed to grow the keywords/rankings with very low volume. Budget is non-existent here, so I can't spend much on AdWords or buying backlinks. The only budget I get is for content creation.

Any strategies I am missing out on how I can do this will be useful! If you have any hidden tricks, let me know as well!