While I am not as experienced in programming as yourself, I would recommend creating a GDD (Game Design Document) first. This is not a 20 minute project as you may spend several hours or days on it.
By writing down all of your ideas and concepts, to include details such as sounds, music, graphics you want to do, features of your game, skills that characters will use, settings, world maps/dungeons, and so on, you can have a clear idea of the project in front of you.
Once this is complete, you have a road map to your entire project. Of course you can change things as you go along, but the framework is laid. At this point, you can now pick a reasonable spot to begin, such as developing the character and their skills, perhaps the progression system. For this, I'll leave it up to you and the advice of a more experience programmer in RPGs.
However, as you begin, you can simply work from this GDD, and you will be able to "check off" things that you've completed and work in some sort of linear fashion, making sure you aren't forgetting anything and capturing all the content you want.
Cheers. (I have a template of a GDD if you're interested)
I definitely agree with the above statement. I thought that when I started learning C# and XNA (I am still new, I started a few weeks ago but am progressing at a decent rate) I could simply start with a "build this game" tutorial online and would understand how everything works in building a full program to start. I can assure you, it didn't work out that way. When they started implementing the various methods, classes, and subtle syntax to the language in the code, I could not understand why they wrote the code one way or another, which, for future game writing, is useless. I was merely copying code and not understanding it.
However, I invested in some real, published books and not just tutorials on the web. I started with the infamous "Hello World" program and have progressed from that. I am now understanding how classes have pre-built methods that are utilized to perform various tasks. I'm still learning, and I'm movtivated to learn by my desire to eventually build a high speed 2-D, and hopefully a few months down the road 3-D, game.
You will be much happier and productive if you take your time and put your dues in learning your language of choice from the ground up. A 3-year old learning a new language can't write a college level thesis, nor can we jump straight into the the meat and potatoes of programming without understand it. Good luck!