Everyone knows that forums are the toughest type of sites to start. It is very common to see so many forums start and close down in no time. Here are the mistakes you just have to avoid if you wish your forum to succeed :
Forums require time to kick off - Forums require time for everything. Right from setting it up and getting members to monetizing it.
As an admin you have to stay active - In the beginning admins are always active but then after a point they give up. That’s not a good sign at all.
Creating too many Sub-Forums - Start small and then increase the sections as required. This will make your forum look really empty.
Stuffing your forum with ads - Let's face it, in the beginning you are not going to get many visits. It is best you don't sell ads till you don't get 150 daily visits.
I recently started a new webmaster forum on my own and from my previous experience I have written this post. Hope you liked these pointers. If you have any more please feel free to add them below.