1. `t`  

Once I've heard a teacher saying never to pronounce the letter "T" with the sound "T", start with the sound "D" [in English]. So she said we should say [di], but not [ti].  

But when I listen to the books, I've heard the French people start with "T", so I wonder, who is right?
2. `p`  

The same as above. Which sound should I start with? Sound "P" or sound "B"?