If you steelman idolatry it goes basic. It's when you worship something that isn't sacred. It's not difficult to make a sacred idol, though you have to be sure not to confuse the symbol for the symbolized target.
Christians obviously have all sorts of idols, it's just not called idolatry because as always Christianity is in fact Satanism and being consistent is heresy against Satan. A non-hypocritical Christian is doing it wrong.