In many news groups and game development forums there are always general questions from newbies that would like to create games. The oldies that frequent these sites give good advice, but the utility of this advice depends the assumption the oldie makes about the experience of the newbie. A newbie may be disheartened by an answer that goes into too much depth, or feel that the advice is too superficial.
I think the question we newbies should ask ourselves is: Why do I want to create a game? There are many possible reasons. For example, you may want to pursue a career in the gaming industry; impress someone with your technical aptitude; explore your own creative genius; learn a new language; or you may simply want to create games for your own personal enjoyment (a.k.a. fun).
Whatever it is, be sure you know the particular motivation that drove you to the task of creating a game. And then stay true to yourself in that regard. For example. if you want to join the gaming industry, my advice is to make sure you explore all areas that is of interest to you, then choose a speciality. Focus all your efforts on learning the current state-of-the-art tools and techniques in that speciality. If you don't like it, switch to another area - and so on. I would also argue that you would do well to ignore me and ask advice from someone that has actually tried to make it in the industry.
For a person like myself that create games only for the fun of it; any advice that does not directly pertain to fun should be taken with a good dose of salt. Now, if we talk about fun - that is a different story. About that we can talk for hours. Soon we might conclude that fun is not objective and it is a very personal thing. But, all is not lost, there is one absolute truth about fun: you are the only judge of your fun. If you say 'that was fun', no one can disagree; and if you say 'that was not fun' no one can disagree that you did not have fun.
So, if fun is your motivator, I propose that you are the only judge of your game. If the game was fun to create, it was a successful, otherwise it was an utter waste of your time. This proposal presupposes that you have in fact completed a game. Clearly, on the road to completion you may have to spend some time (hopefully not too much) that may not be fun. But take heart; this process is like any other worthwhile human endeavour. The acquiring of fun is usually preceded by the attainment of a reasonable level of skill. The pursuit of the latter is filled with toils and troubles that are overcome only by an adequate level of personal commitment.
Of course, when your aim is to have fun, your level of commitment is relatively low. You quickly recognise problems that are far beyond your current skill and promptly avoid solving them. This is a fine approach, but it may be problematic. This is mostly because creating a game for fun is not a competitive sport, like tennis for example. You may enjoy playing tennis without ever thinking about becoming a tennis pro. You like to play tennis with other people that are more or less on your skill level; and as they get better, your game may also improve. If your competitors always beat the living crap out of you, tennis won't be much fun..
Likewise, when you create a game, and you evaluate your product with the product of a professional game studio, creating games won't be much fun. You need a good competitor. Realise that the only competitor you have - and the one you must always strive to beat - is no one else but the previous version of yourself. So it is very advisable to start with Tic-Tac-Toe or some other simple game. This way you create a worthy opponent; an opponent that has drawn a line in the sand, and dares you to cross that line. For your next game, you must focus on giving that opponent a real beating - and then draw a new line in the sand.
Before asking on a forum which is the best language, the best platform, the best graphics engine for creating games, or the best game idea, first ask yourself what is more fun for you. For me, it is currently more fun to program in C++ than in Java or in C#. It is more fun to use OpenGL than it is to use Direct X. It is more fun for me to use SDL than it is to Orge3D. These are assertions I make because I have explored these (and many other) choices. And I had fun doing it.
Go ahead, start working towards that vision of a game you always wanted to write. But start by creating a lesser game - a game you know you can write. Take that first step; who knows where to it might lead. It could even be fun!