Ok, so I mostly enjoy pc simulation games, e.g. the old champ managers, chart wars, etc...

The way I did my first game was to choose a small game that I enjoyed and found fun, it was a trading based simulation game, I set out with the task of programming a clone basically, may have seemed pointless to some but it helped me learn a huge amount in the process.

Then once I got the basic fundementals working I started expanding and improving upon it with my own ideas, adding mini games and random events, a cheats system, high score list etc...

The biggest advice I can give you is to always write down every single idea you have no matter how far fetched it is, what seems impossible when you think of it could turn out to have a simple way of making it eventually, and always have a pen and notepad with you at all times, I've been on the bus on my way home from work when I have thought of formula's and ideas that would benefit my games programming, and my little notepad helped me out lots lol.

First of all i appreciate your approach. Developing a game is not a simple task. Even i started on my own and wasted a lot of time even for designing a simple game for myself. Later on i ended up pursuing a course in video game designing and realised that it consisted of three parts including the game designing, game art, and game programming. I suggest you to pursue a course that will teach you all the three.