I would say if you're going to make an RPG, the best thing would be to play a few and take away what you felt was the best part of the game you played. For me, my absolute favorite is Final Fantasy 4, and the best thing about it is the storyline. I've never been much of a big fan when it comes to combat, I'm more of the "Press X to Jason" type: Battle starts > tap X to keep attacking until battle is over > Continue game.
I've been using RPG Maker on and off for almost a year now. I feel it's a great tool to be able to make the type of RPGs I fell in love with, particularly old-school NES/SNES types like the Final Fantasy/Dragon Warrior series. My only setback, and the reason I haven't put out a game yet, is because my art skill have dropped off drastically since I finished high school all those many years ago, and I'm not a composer. I'm more of a storyteller, so creating the actual adventure is my thing. And far as I'm concerned, stock graphics and music are nice if all you strive for is a game your friends are going to play, but custom graphics and music are what will differentiate your game from all the others.
But really, a storyline filled with creativity, humor, and even drama goes a long way. And more than anything, perfect spelling and grammar is key in a game where 95% of it is reading.