When I got my M&P (new), I disassembled it and cleaned it. Then I lubed it as follows ("grease" is synthetic axle grease - I happen to use Valvoline DuraLube):
Thin coat grease on the firing pin, with the excess grease wiped off.
One drop of Remoil (or your favorite gun oil) on the bolt's gas rings.
Grease on the lug (not in the hole of the lug, just the outside that comes in contact with the bolt carrier).
After the BCG is reassembled, wipe it down with a cloth, and apply grease to the rails (or what could be called rails).
Apply grease to the top/sides of the charging handle, and then wipe off the excess.
On a new rifle, I oil all the pins on the lower as well. One drop each is enough.
Make sure your chamber is clean.
One thing you didn't mention is your magazine. It could be defective.
Also, you didn't mention what ammo you are shooting, but if you're going to use steel-case ammo, avoid switching to brass (or vice-versa) without cleaning the chamber first.
A couple of people have mentioned that a new AR should be run "wet", but I don't really see the need.