I have good luck dictating text in Mail or Messages. It has trained me to be a bit more precise in enunciation and to be care to say each word distinctly, but I probably should do that anyway. And one other thing, never dictate with the television on. You can get some really interesting results that way, but it is unlikely to be what you want.
thanks Ira will look, no apps invented that do keyboard shortcuts that turn in to blurbs?
On the iDevice that is exactly what "Text Replacement" does. Set it up in the Preference and, for example, when you type "yt" on the keyboard, you will get "Yours truly,". Pick your key combinations and the associated replacement phrase.
Keep in mind that the iDevice keyboard is more limited—no function keys, no command, control, option, etc.