Yes you can. What do you mean by more popular day by day but less visitors? Isn't popularity measured by traffic?
Header yeah, you know core of a forum is header. the first attractive place for users are this header so create a logo with a lovely description.
Yes, of course. All you need is just apply the google ads through google. For big earn, you must have big effort, especially for getting a huge traffic.
Yes. But you should be developing backlinks and other social links to your website to get good Google rankings.
In my experience new relevant content will get the Google spiders to reindex your site. I had a site that simply spun the articles every week with the idea of getting Google to keep coming back to look at the "new" content. Do a Google search on Adding a site to Google webmaster tools help to get it straight from Google
Hi, you can do seo and sem for that site and also smo these three will help to bring the traffic as well as you site will get ranked with quality links. For these you can go with some internet marketing company.