I understand that it's difficult to have a good and loyal followers without paying them. It will help generate traffic to a site. It is always better to consider posting good quality content to a blog or forum. It should be useful and informative. It will attract audience or users to know the site better. It is also nice to have an interaction with your audience or guest. Sharing thoughts or opinions makes a site lively.
According to my knowledge the below mentioned metrics will be helpful in increasing organic traffic.
Content Marketing: For SEO content generation is the top most priority for any company to describe their brand to the world of internet, generating content does not complete your work we need to market it accordingly to your niche, industry so that it can readable by the users and provide their opinions on that.
Keyword Research: Having keywords in your website content which brings you traffic is a really effective so choosing keywords which matches your buyer persona is really important and also need to optimise your keywords accordingly with your content makes it more effective.
Longtail keywords this is one of the main aspects everyone should follow while doing keyword research because they not only bring you traffic but also are helpful in rankings other keyword phrases, user normally search for long tail keywords.
On-page Metrics: To make your sound technically good they you need to take care of your on-page metrics which makes a complete website, it starts from meta tags, image alt tags, header tags, robots, sitemap, schema, audit, tracking codes, 404 page, redirection, this are the basic things which need to be their for a website.
Off-page Metrics: This helps you gain traffic to your website by doing promotions for your targeted keywords which you would rank, and again it depends on which industry you’re into because not all metrics would not favor your business.
1. guest blogging
2. slideshare presentations, info graphics, bookmarking, articles, press release, classifieds, web 2.o, business citations, directories, blog commenting, this should be submitted in your niche only.