It's definitely not the only way, it's just the quickest... if you're lucky. Otherwise you can be involved with commenting and voting other people's comments. I'm actually running a "giveaway" where if you comment on my post about how you found steemit, I'll give you an upvote. I'm currently worth about .11 per vote. You can get to that post here: https://steemit.com/steemit/@robsteady/tell-me-how-you-ended-up-at-steemit-and-get-an-upvote