The graphics and music can be solved later; you can use some temporary graphics while you work on the program.

According to my research, RPG Maker has a lot of built-in tile graphics you can use if you don't want to make your own, so I could use them. I think the default graphics look kind of like Final Fantasy IV or Final Fantasy V.

Could you be more specific about the RPG? There are many options: isometric or 3d, turn-based or real-time... Will it have a story, or just a lot of random fights? If the story, will there be branches and multiple endings? How complicated it the system of magic or whatever (is it enough just to attack and expect that a higher-level character automatically does higher damage, or is it necessary to use a proper action to solve the specific situation)? One character or a party? Is the game over when one of your character dies, or do you just recruit a new one? Etc. -- Think about how your choices fit together. For example, if the world is automatically generated or you replace dead members with new recruits, how will you keep a meaningful story?

I want to eventually make a story-driven game, with two endings and a few branch points that can pull you off of the default branch; the specific details of the battle system is not particularly important. (Although it might be nice to be able to pull off some tricks with the battle system, such as presenting you with two enemies fighting each other, and giving you a different story branch depending on which one wins.) I might start with something simpler than the story I really want to tell, though, just to get experience with the system I intend to use.

One reason I want to tell the story as a game, rather than as text, is that I want to set the player up for a fall: start the player off working for the bad guys, and give the player the opportunity not to realize that the side he's working for is actually evil; the player character won't make a Heel Face Turn unless the player does something special to get off the default story branch. At the end of the game, the default ending will show the player several times he or she could have done the right thing, but didn't.