How do you use Reddit to get new users?

I think Reddit could potentially be one of the best places to grow my startup. I found my beta testers on a few beta testing subreddits and got some pretty good feedback and engagement on my posts.

Now that I've launched, I think Reddit could be a great place to introduce my app to a bunch of people in my target audience - I have an investment tracking app and there's no shortage of subreddits dedicated to investing topics. The problem being that I'm not sure exactly how to go about it.

Pretty much every subreddit I come across that could be a good place to post has strict rules on no promotion, solicitation, or marketing. I'm not trying to just blast out a half brained post about using my app, I genuinely think it's useful and people can benefit from using it - especially the people in the subreddits I'd target.

I should also mention I'm relatively new to Reddit and have to admit it's kind of intimidating to me. I feel like there's a lot of unspoken rules in some of the subreddits and people can spot fresh meat from a mile away.

Any advice on how to leverage Reddit, or any reasons to avoid it?