I wouldn’t pay too much attention to the reputation score. It’s a bit of a gamed system. It depends on the upvotes you get. If you get a lot of really strong upvotes worth like 10-20$ on your posts then your reputation goes up. Same is true for down votes, people who plagiarize stuff, harass people or beg for upvotes usually get down voted pretty fast and strong. This kills their “reputation” as it’s known. I would spend time on the content and the comments. The rest will come with time! Resource credits are a relatively new phenomenon but they are required. It’s a way to calculate the cost of a transaction on the chain and it helps a lot to reduce spam and stuff. You have to have a minimum amount of hive power to interact and if you are looking to be a jerk and spam all kinds of stuff you won’t get far unless you buy hive to do it. Most people won’t do that so they will spam for a little bit, get annoyed they can’t keep going and leave. 

I’ve been here nearly 4 years and I’m still learning stuff so don’t sweat it! Lol

A good cadence if you're looking to post long stuff is once a week. 

If you are out there looking to comment, the Ecency front end is the best. You can interact with people on the chain with votes and comments and things and that earns you points which you can use to "boost" (vote) on your posts. A boost can be anywhere from 1$ to like 5$ but the owners of Ecency manually review the boost requests. It's a really good way to help get yourself some hive power and it helps reward you for doing good things like commenting!