Want to learn how to play a role playing game? First step: play the damn game, nothing substitutes for this. There is nothing like that ‘A ha!’ moment when you see a game mechanic in play for the first time. It makes such a big difference in learning to actually play the game. And many a game may seem cool or boring until you play, see how it works, and then it all makes sense (or not as the case may be.)
But my second favorite way to learn a game and a system is to make characters. Sit down with the rules, some scratch paper, maybe a program or App if you have one, and work it out. Doing that can make a huge difference in your knowledge of the rules. That is one of the reasons why I changed characters after my first one in my Denver game. I didn’t really know what I was doing the first time around, and didn’t really grasp all the nuances, what would work, what wouldn’t, what goes where.
(Caution, I am now going to do that which often bores non-players to tears: describe characters)
My first Pathfinder character was a concept I first came up with when I bought the D&D 5E Players Handbook. It was a Gnome Monk, and I envisioned a Yoda like character. I thought it would be pretty cool, and I still think that in the right game and situation it would still work. But, even with the boosts that the GM handed me, he just couldn’t do what I envisioned (part of that is the system, Pathfinder works against tactical movement.) That was my first go around, and I made him using primarily an application, and it just didn’t work properly.
I am now on my second character, a Half Orc Ranger. He has undergone a few alterations as I learned the system and the campaign. He went from a traditional Ranger to more of an Undead Hunter, choosing certain skills, Feats etc. to make him more effective at that. As a result he is considerably more effective than the Monk, and also more useful to the group.
Now, being a tinkerer I decided to create another character, as a back up should something bad happen. And I went in a very different direction. I created an Elven Monk-Sorcerer. The story is he started out as a Monk, but began to feel the urge of his blood, and left the monastery to pursue Sorcery. Obviously he would not be the combat monster that the Ranger is, although I can make a few changes to compensate for that. But more importantly I think I did a far better job of crafting an effective character. It is one of the reasons I rarely start with spell casters when I make the first characters, because those are harder.
After all of this exercise I feel I really know the system now. And that is really why I do this, and do it in almost every game I have played, because making each character tells me a little more about the system. And it is a fun exercise to boot.