best approach to do content marketing?

Start with the questions customers already ask you. Sales calls, support emails, comments. Those are topics you know people care about, and you can answer them better than anyone writing from a keyword list. Pick one format you can actually keep up (one article a week, one video, one newsletter) rather than trying to be everywhere. Then spend as much time getting each piece seen as making it: send it to your email list, cut it into a couple of social posts, link to it from related pages. Give it three to six months before deciding if it works. Measure leads or sign-ups from those pages, not just traffic.