I don't decide who they are, actually. I just realize that I like them a lot plus than others. For example, I'm a huge fan ou Norway, but at first, I didn't think too much of him. But then, as I got plus into the Hetalia fandom, I realized that I liked Norway, because I'd be like, squealing over every fan art I saw of him. Hahaha... I don't know how I came to like him. I just started to like him for some strange reason.
(Aw, shoot man, I can't source this because the original image doesn't exist anymore. :( )
toi don't exactly decide. At least in my opinion. Anyways, most of the time your favourite characters can grow on you, others toi find toi start to like over time, ou in some cases a character toi grow to like even though toi didn't like them at first. Some times characters can become your favourite right away. -smiles-
The way Prussia became my most favourite character was an over time thing. At first I actually didn't like Prussia. I thought he seemed loud and kind of obnoxious. After awhile, I started to see his character plus and his personality. He then became my most favourite Hetalia character. I absolutely just l’amour Prussia and I admire him. He's utter perfection in my eyes.
I agree with Ren-Chan. toi don't have to decide who are your favori characters. toi can like a character from the beginning, but sometimes toi have to take time to get used to some of them.
I already loved Italy before he a dit his first line. I could imediantly tell that he'd be my favori character from the show. However I didn't like Prussia at first, but he grew on me after a while, and in the end he became my seconde favori character.
I don't know what to expect from the characters in a montrer so I can't exactly specify a fixed criteria in choosing a favorite. I just realize, ou as what toi say, decide the character is my favori when he ou she has proven to be the one I look vers l'avant, vers l’avant to the most in the montrer and artworks. In most cases, they're the ones who have: a.) interesting, intriguing personality ou character background/past; b.) They say ou do the cleverest, wittiest, most amusing lines/acts.; c.) They are prime movers that set the plot in motion and are emotionally and mentally involving. (Now, I'm not pertaining to thorny kuu guys with emo tendencies.). Well, that's how it goes, generally speaking. In Hetalia, my haut, retour au début picks are Austria, Prussia, Germany and England who I equally like. Besides the fact that I have predilection for anything Germanic, these characters have complex ou simply interesting personality, they are plus than meets the eye (which makes me wonder plus than any other characters in the story), and there really are something intriguing about their past featured par Hima about them that really make me go figuring out, and they have that surprising kind of humor, I just l’amour their scenes, so that makes them engaging to follow thus that's how I know that indeed they are the apples in my eyes.