Having more SP will increase your voting power. The fastest way to get your rep score higher is to interact with users with higher rep scores than you. If the higher rep score users upvote your content, your score will rise.

Having more SP will not outrank your content over someone with less SP. With more SP, you could however upvote your own content, which would then rank higher than a fresh new post with no upvotes.

I would recommend that you use steemworld.org/@YOURUSERNAME to track your actions and how it affects your rep score.