So your diagram should have :
between O and C, double bond, so "xoxo"
between C and each N, single bond, so "xo"
between N and each H, single bond, so "xo"
make sure your O has two lone pairs, ie. "xx" and "xx" (not
bonded with C)
make sure your N has one lone pair, ie. "xx" (not bonded with H
or C)
check that total no. of valence electrons (both bond pairs and
lone pairs) = 12 pairs = 24 valence electrons
