How long does it take for a new blog to get traffic if it has around 20 blogs pots and has been established for 20 days? What things do I need to submit to Google for organic traffic, promoting on social networks or forums to drive traffic to it?
Your blog can get traffic right away, like today even, if you go promote it the right way to the right audience. It really depends on your situation. Everything you are asking depends on your specific situation and a lot of variables.
Here are some examples of how long it might take using various methods:
1) If you are a new blogger who is writing about whatever topic interests you at the moment, and you are not doing any promoting whatsoever, then you will probably NEVER get any meaningful amount of traffic to your site. The reason you will probably NEVER get any meaningful amount of traffic is because you won't find very many random people who want to read your random blog posts. Those types of readers are extremely hard to come by. They are out there, but they tend to only read blogs from people who are really interesting. And in all honesty, most people can't write interesting blog posts even if their lives are actually interesting.
2) You could create a high quality niche blog (authority site/blog) where you only write your highest quality possible blog posts and try to make them as useful for your audience as possible. Then you rely on SEO and referral traffic (people telling each other about your site) to generate your traffic. If you follow that approach, then it depends on - how well you do your SEO and how many people are searching for your keywords. In general when taking this approach I find that traffic will ramp up slowly over the course of about six months. After six months the blog is usually getting a lot of traffic compared to the size of the niche and the exact keywords you are targeting. The first couple months you will get very little traffic at all. After month two your traffic will start to increase a little bit each week.
If you want to promote your blog on forums, then find forums that have the exact audience that will like your blog. Then join those forums and just start talking to as many people as possible being as friendly and as helpful as possible. The more helpful you are and the more likable you are, the more traffic you will get to your website through a signature link or signature advertisement.
Really, the best way to promote your own website is to focus on building as good of site as you can (to the best of your ability whatever that is). Then just go wherever you can find other people like you online and start building real friendships. If you build up real friendships with other people online, then they will tell other people about you. If you do that, you will get traffic to your site from a whole bunch of different sources. You have got to build friendships that are deep enough for people to want to do that though. And you have to have a website that is good enough for people to want to tell other people about.
