The right of self-determination as enshrined in the Charter of the United Nations is in practice somewhat qualified; to cut a long story short, it doesn't permit bits of existing nations to secede as of right, even if they have an overwhelming referendum result behind them. Otherwise the Basques, the Cataluns, the Tamils, the Cornish and God Knows Who would be seceding all over the place.
So sorry, Crimea, you've gone about this the wrong way. The ballot box and peaceful referenda are not the way to international recognition. You should have done what they did in the spanking brand new nation of South Sudan; waited until the new neo-fascist regime banned the Russian language, then embarked on a terrorist campaign of bombings and guerilla attacks. The Kiev neo-fascists would react violently and repressively, and there would be ghastly war-crimes and atrocities all over the place. After a few tens of thousands killed, Robert Fisk would have made a documentary programme and the UN would have brokered talks to secure your independence.
See where you went wrong there? Not enough dead people.
(NB This post is irony. This blog does not condone, support or advocate terrorism in any form.)