Think of the plot and the idea of the game you want to create. Be it adventure, race or variants of a fight, you decide. It should be understood that the game creation process tedious and requires a lot of time. Without specific knowledge to create a game you do not get. You need to learn the basics of programming languages, scripting languages, simulation.
Select the format of a game is 2D or 3D. Easier to do 2D than 3D: they do not load computer, and the amount of programming needed to create the game, is minimized. But even to create 2D games need good to be able to draw. If you can't draw, you can use ready-made blanks of locations, characters, etc.
One of the advantages of 3D games can be called the beauty and the spectacle, but the beauty demands victims, so the immediately visible drawbacks. You will need knowledge of different programming languages. It is the most difficult part of creating 3D games. It is assumed the more difficult the game, the more difficult languages. Their huge variety and they are known for a very long time. Learning one language you will face the necessity of knowledge of the other. And so on increasing. Another obvious disadvantage is that you need powerful computers. To draw here is not, but you need to learn to work in programs for modeling, but it is not easier drawing and without imagination can not do here.
There are special constructors for creating games. Of finished parts that you are given in the constructor, you will eventually create your game. They are suitable for both 3D games and 2D games. If you don't have ready parts, then you can add your own and use them. To force something to move, you will need to assign object actions using logical operations. With a shortage of standard actions to come to the aid of scripting languages. There are designers that include common programming languages, they are more functional, but their work is more difficult to grasp. Designers usually are divided into genres, but there are common that are suitable for creating games of various genres.