How to get huge organic traffic nowadays ?

Huge? define that.

You don't want HUGE traffic, you want TARGETED traffic. You generally want people who are interested in your product/service, and are ready to purchase.

Content is the best method if you're going strictly organic.

To start with, there is a world of hard dedicated work and sweat between the words "huge" and "organic".

It would be nearly impossible to answer this in one, or even 100 posts, as it's a combination of a million and a half things.

Product/service category
Time in business
Competition
Demand
Location
etc.

And these are just the basic things to start the conversation with. Techniques you may be using vary for each and every product/service.

For getting actual organic traffic you would need quality appealing content.
Also your website must be updated constantly, as it's pretty easy to get it ignored if it doesn't looks like it's an 'alive' site.

Content marketing is a good way to generate organic traffic to your website from various external webpages.

Write consistently quality and engaging content. Stay away from duplicate content.