An earlier post covered the appropriate greetings and closing for business correspondence in Spanish.
But before sending a business email to ask someone for information, STOP and ask yourself, "is there another way I can get this information?"
Is it online?
Is it in a document you have or have access to?
Will you see a friend or colleague in the near future who can give you that information?
In a professional context, an employer won't want to walk you through every single task--especially if it involves information that is readily available elsewhere precisely because so many people need that information so often.
Likewise, an employer isn't going to want to work side-by-side with you on everything, thus burning two man hours for every task that only requires one.