For many species close examination is needed to get an ID. This entails collecting a specimen. Fortunately there is a good book for species ID in northeast NA "A Field Guide to the Ants of New England", Ellison et al.
Three common genera in my area are:
Camponotus A & B, A= C. pennsylvanicus Eastern Carpenter Ant; B= C. herculeanus The Great Carpenter Ant
Formica C = F. aserva The Slaveless Ant
Myrmica sp. D a minefield for getting an accurate specific ID.
These 3 genera are readily separated when seen in lateral view:
Camponotus species have a smooth convex mesosoma;
Formica species are the 'broken-back ants';
Myrmica species have a 2-segmented pedicel (1 in the other genera) and 2 large propodeal spines.

