DON'T: I send 2 billion troops to surround every single one of your ports and borders! (country was founded 5 days ago)
DO: We start sending shy of 5 thousand troops to your borders.
DON'T: I use my orbital death ray to destroy you in 0.00000069420 seconds!!!!111!1!1
DO: We start sending tanks about the size of the average family home into the battlefield.
DON'T: our soldier get in
DO: The Land of -insert_nation- initiates war efforts to start sending troops. The troops gradually surround about 15% of the country before charging in at a good pace.
DON'T: I sent 294848483 nukes to you so hahaha
DO: The president initiates a singular nuclear missile; the missile to hopefully end the war.
BONUS: Remember! You don't need to have the most in-depth explanations for copious military know-how to RO! All you need is to remember to have some sort of level of realism! ;)