Comment on people's hubs, and interact with them. Some will go and read your hubs and decide to follow you.
Also when you follow people, they may go take a look at your hubs and follow you too.
Also publish good content that people want to read. Some will find your hubs while they are surfing around and decide to follow you if they like what you have to say.
Interact with people and their hubs and you will find people do the same with you. It is part of marketing your hubs. Writing the hub is not enough to draw in lots of traffic, you do need to put some time into marketing them.
Also read other people's questions, answer some of them etc.