hi there...
As far i kno..the stability order goes lik this-
Atleast for resonatin structures
1) the one with more covalent bond
2) all elements shld 've octet configuration (in the compound)
3) uncharged species are more stable than charged species
4) -ve charge shld b on the most electro -ve species or element (n same for +ve)
5) in charged structures most separation for like charges n same for unlike