How to steal part of a country

Step 1: "Provide support" for members of said part of country who are unhappy with existing Government
Step 2: When Government finally gets angry enough to send in the troops, Rush in to "defend" with overwhelming force. For bonus points, shoot up parts of the country that have nothing to do with the bunch you're defending. High-value targets like airports are good, even if they're on the other side of the country.
Step 3: Give passports to all the members of the part of the country
Step 4: Ignore repeated, desperate requests for ceasefire from stunned, over-powered Government. Shoot a boat or two.
Step 5: Deploy humanitarian aid for all the victims, including large, rather permanent, military hospitals
Step 6: Finally agree that maybe we could have a cease fire. Get really prickly when anyone suggests moving troops out. If you need to justify anything, maintain they're defending previously installed humanitarian assets.
Step 7: Refuse to leave. Rely on the fact that the only people with the weaponry and motivation to do anything about it have already got themselves into a nice quagmire half way across the planet. If necessary, create a "protectorate" status for a few years to maintain some fiction of self-determination.

There you have it, the 7 step plan to territory acquisition with moral pretext bonus.

*Please note, I have no opinion whatsoever on recent world events with a remarkable resemblance to the above, I know absolutely nothing about the area or its politics