My best advice is to remain active on Steemit. Even if you are not creating posts regularly, comment on others posts, answer comments on your own, join discord groups.
Bear in mind that as nice as it is to be a part of many communities, it can be exhaustive and time consuming so you will want to set realistic goals in regards to time management for yourself.
If you do decide to join any specific communities, ensure that you show support for the members who are already established. You can do so by commenting, and/or upvoting their posts, following them, ect.
Try using the Steemit search feature, and also look through popular tags, you would be amazed as to what you stumble on this way.
My last bit of advice is to remain respectful to all the members in the communities, even when you may not entirely agree with what they are saying, or even if they are being rude to you. This may seem like a common sense statement, but you would be surprised just how quickly a persons rep can get destroyed from saying things without thinking first.
Good luck, and best wishes to you!
Thank you for all the advice @futuremind, @valth and @jlordc! (: