Community building can mean many things. It may refer to networking with peers to find mutual benefit and learning. It can also refer to creating a group of loyal and connected fans around a brand, business, interest, or cause. For the latter, here are some examples of ways to build community:
Start an online community through message boards and engage with members often.
Host book clubs or other IRL meetups in your space.
Participate in discussions with community members of groups with a crossover audience.