There are a myriad of ways to find a group. Usually people are shouting for specific classes in Mor Dhona or sometimes in Grand Cities too.

Aside from that, there are LSes one can ask. Most people tend to have at least one or two LSes and it's too easy to ask a buddy "Hey, can you maybe find another person that can join us?" and what-not.

Not only that, be sure and edit your search info to let people know what type of dungeons you're looking for. In addition, there's always the Duty Finder at earlier levels of dungeons.

There are plenty of options. I don't think that it's hard to get a group unless you're specifically standing and being a mute wanting someone to invite you because you're a particular class. If people are shying away from you, be sure to shout that you're a WHM looking to make people feel good in battle. They'll jump on it.