http://en.wikipedia.org/wiki/Micronation#New-country_projects
The rest of the article is also relevant. Note the bit where it says
(few of which are ever realised)
Just about every established internet community has had this idea at some point. /b/ being the excitable hive mind that it is, you may actually pull it off, though I really,
really doubt you will.
Now if I were you, assuming you're not actually one of the aforementioned 14-year-olds, I'd assemble a small, dedicated, mature and capable people. Together, create a realistic concept for your ``nation'' that will be attractive to the press, whichever
real nation you're doing it in and, of course, tourists. You're not in a position to piss people off.
I know it's cool to have a pirate island that gives a big ``fuck you'' to whichever government legally owns it, but you need to compromise if you actually want your effort to pay off.
So basically what you're doing is getting some property you can work with in a country that wont hire assassins and bulldoze your shit as soon as it finds out. There you'll be making a pretty place (like a really cool back yard with water fountains and shit, or just hijack part of a forest), then contact your government and tell it you've created a tourist attraction, and say the sovereignty would be a gimmick. If they go along with it, tourists will of course need to come to that nation to visit yours, so if your government is particularly gay for this shit (Netherlands, for example), and everyone lives happily ever after.
The order in which you pull off all that shit is up to you. You could instead ask your government for the right to build your pretty garden (or town, if you happen to have rich parents) first, and either suggest the micronation tourism shit to them once it's finished or you could be a dick and declare it sovereign yourself, though I doubt they'd recognise it as such. Or just pull an Israel and build without permission and then notify the press.
I really do recommend you do this in a forest. It's safe, secluded, easy to work with and the government is not likely to give a shit. If you can spare the money (which you really should), hire some professional landscapers and gardeners and shit. A pretty garden is the best bang for your buck.
Just my 356 cents.