Why is secrecy such a value here in prayer and fasting? It must be because God wants to contrast the inward nature of true spirituality with the external show of false spirituality. Jesus is not advocating the neglect of spiritual disciplines; they are still done. They are just done differently. He is advocating care about our motives as we do the spiritual disciplines.
The advice about prayer is, "Don't. . . Don't. . . Do. . ." Don't be like the religous. Don't be like the pagan. Do pray like this, "Our Father..."
The Lord's prayer has interesting form in the Greek language, one we don't have in English, third person imperative. That's where the translations of "LET your will be done." It is different than "Do your will." It shifts to second person imperatives, which you would expect, at "Give us this day..."
Interesting, too, that the bread is for today, not for later.