This type of micronation is surrounded from all sides by another state (or at least on most sides -it can border the ocean). This means that any attempt at being accepted must take this 'mother country' into account, and will be most likely decided by it.
Civilization with all its trappings should be nearby.
The small distance towards a state means an intervention into the fledgling state's affairs is much more likely. Also, any (possible) negative backlash from the public will be felt more.
Preventive measures/solutions: concentrate on positive P.R., and design ways to keep the bureaucracy busy.
With civilization nearby, basic survival may be much more easier than in an isolated place (unless there is a blockade). It should be easier to find business partners, and earn money due to different legal standards between the countries.
Mostly started in abandoned or out of way locations, with unclear property rights. There are many such places, there may be entire neighborhoods or ghost towns available. The success will depend on more factors than that.
As an alternative for of independence, one could buy an entire town and become its owner and mayor.
It is difficult to tear away a part of a state's territory, and declare it for one's own. Doing it inside of the state is still more difficult. At the least, one can expect legal challenges.
The Principality of Hutt River, an independent territory in Western Australia, founded in 1970 after a long-running dispute over wheat quotas.
Freetown Christiania is a partially self-governing neighbourhood in the Danish capital Copenhagen.
Somewhat established is the Northern Forest Archipelago, more of a natural preserve movement in the north of the US; note that they don't seek secession.
(more examples and attempts)