Don't worry about a name or a domain or a hosting or whatever. Just slap it together in the stupidest way you can. You wanna make a game? Build the gameplay with colored blocks moving around in some crappy toy game-making app. You wanna make a web app? Shit something out in PHP.
If your utterly shitty implementation of the idea feels like something worth pushing further, then you can start investing in Doing It Right.
This goes for any field, by the way. Obsessing too much about a painting? Grab a crayon or a highlighter or whatever and some cheap paper and make a few messes until you have something that actually works, even in its shittiness of execution. Making music? Just plop down a few chord progressions or some little doodles of melody or rhythm, until something has that spark. Writing a story? Scribble down the barest outline of the plot and ask yourself how many cliches you can count, sit down with a bottle of wine and a notebook and a list of interview questions to pick from to ask that character who's sitting in the back of your head and won't go away.
Whatever you want to make, make the crappiest version of it you can, and then start refining it.
And if all of your ideas are too good to sully with this, don't sit there. Put them in a notebook, and come up with some throwaway ideas that you're perfectly fine with doing shitty versions of; this will hone your skills, and eventually you can look at that one shining, amazing idea that still seems like a good idea twenty years later and decide that it's time to have a go at it.