You earn more steem dollars and steem power in two ways:

• Upvoting other people's content (curation rewards)
• Receiving upvotes for your own content (author rewards)

To do the former, just read people's posts and upvote the ones you like. The latter requires some thought and care, but also will result in greater rewards if you stick with it.

Or you can just hold the steem you have. It's been increasing in value quite significantly recently, and will likely continue to do so.