I can understand the visit part, but what do the other things mean? How does it get affected (go up or down)?

Well, "favorites" rises as more people favorite your comic. You know what visits means, and I'm actually not too sure what growth means. I think it determines how fast you're rising towards the top 5/10/100.

Growth rate is how fast your comic grows.

Update more often and it goes up. Start updating less and it goes down.

That really explained it for me. Thanks.