If you own the forums the best thing to do is for your self to be the most active member on the forums.
I start all sorts of topics, discussions on my forums and they are pretty busy. One add on that I use on our forums is the awards system :
https://vborg.vbsupport.ru/showthread.php?t=232684
Since we are a gaming clan and community this keeps our members very interested in not just the awards but also activity on the forums.