I've ended up in the old staff picks section and more recently in new and noteworthy, but I still don't know what the magic formula is!
I try to have an attractive icon, make sure that the first few episodes of my comcs have a lot of juicy content and are as good as I can make them. It's possible that the fact I have a few completed series on Tapas helped (a track record?), and it's possible that it helped that both comics were slightly unusual genres that might not have been competing with as many other new comics for the spotlight (I'm guessing there are lots of new romance comics around, and not so many sci-fi).
I would note that getting featured is lovely, but I wonder sometimes if the effects are a little bit superficial, particularly if (like me!) your comics are a little bit niche. I had lots of new subs, lots of unsubs a few weeks later, and not massive longterm increase in views. The best outcome for me was that it opened some doors when people with interesting projects outside of Tapas saw my artwork and were interested in me as a creator.