What should they talk about :
Very broad, won't you say? It could be anything! the food, the movie, other people, ex-boy/girlfriends, hobbies, music, sex, sports (though, not every woman likes that one i believe), etc. It depends on the date i think.
What should they wear
Ah yes, all black but that means very depressing. All white means easy spots. Something colourful would suffice ; im not into women's clothing.
Men should wear something neutral. Not too many colours, and not combining green with red or something like that. Just, dress like you not going to a frat-party.
Where should they go
You do NOT want to go to the movies! No conversation, which means no chance for a second date! Go ice-skating, go to a soccer-match, at least do something both can laugh about and enjoy at the same time. Always combine the date with diner ; not use diner as a date

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How should they act
Like everyone would act like him/herself during a first date

. I guess trying to be interested in the other. Let them do the talking and only ask something when there's going to be a long silence or when you must answer a question.
hmmz, with everyone in this topic we might get the ultimate date!