How I grow community on my site
Give them plenty of options to subscribe to the site/create an account and consistent flow of content they want to consume and share.
Well it is about gaming
Hi, @Luka Miladinovic! This is a million worth question :)
What is your community and site about?
I'd emphasize key attributes of the successful forum: the content itself, as @Cam Papermaker mentioned, and its segmentation within the forum (your side), forum functionality (our side) your, as owner's, activity (your side), marketing (your side).
If you'd love me to guide you through the forum main functionalities, let's have a call :)