Infarct localization is quite easy.
II, III, aVF - inferior MI (form a letter "L" for "low")
V1 only - septal
V2, V3, V4 - anterior
I, aVL, V5, V6 - lateral
II, III, aVF and V1 looking like an upside-down MI - posterior
I and aVL only - high (superior) lateral
These can also combine. E.g. V1-V4 anteroseptal; I, aVL, V3-V6 anterolateral, etc.
To very grossly generalize (coronary anatomy is quite variable):
RCA supplies the posterior wall.
LAD supplies the anterior wall.
Circumflex supplies the lateral wall.
Inferior wall could be RCA or LAD
Since circumflex comes off the LAD, a high LAD occlusion will take out both vessels and cause anterolateral MI. An osteal occlusion will also involve the septal perforators and grab the septum along for the ride.