i did pu/pd in the night when she woke up but i didn't think she was genuinely hungry (she never took much and when she did eat in teh night she would then hardley take any in the morning)....it won't work if they are waking due to hunger, or pain etc. you have to be sure the NW is due to habit or something like that or else it's not the right thing to use.
anyway... she would cry, i always waited a bit to see if it was mantra or a i need you cry before going in as sometimes she would settle herself. then i would go in and comfort in the crib with shh pat first. if this didn't work to get her back to sleep and she really escalated i would pick her up but keep her horizontal, no rocking or anything. as soon as she stopped crying or switched to mantra cry or struggled against me i would put her dow and continue with shhing. most of the time i was putting her down pretty quickly because she was really struggling against me. after 6 mo you're supposed to only hold them for 5 min and then put down even if still crying and pick right back up again. the techniques change with age and abilities.
if he's smiling and happy, i would avoid eye contact and make it as boring as it can be. you don't do it if he's not really crying and you always try comforting in the crib first. makw sure you're not rushing in too soon
the first night i was doing this for 90 min
it was he**. the second night was almost as bad. the third night she slept through
then it was on and off for a few nights until she then very consistently slept through.
the pu/pd board has other great tips and the ladies there are much better at describing the techniques!