I write like I talk, but I try to use correct grammar, syntax, spelling, etc. I'll type things like "ain't", "y'all", "prettymuch", "gonna", and stuff like that, and I'll combine words like I would in casual speech ("d'you" for "did you", etc.), but I'll usually put in the correct punctuation where it's needed.

As for collective names (Square, Texas (team), etc.), they should not be pluralized. It would be "Texas Rangers are bad", "Rangers are bad", and "Texas is a bad team." "Texas" is not plural, however, the word "Rangers" is plural. It would depend on the context, I believe, but I'm not sure.

And when I was young, I was taught to put a comma after everything in a list of more than two ("this, that, and the other"), but later in life I was taught different. I've always used the comma, though.

Y'all Brits need to stop putting "ou" where "o" should be--color, armor, and the like.