An example of foreshadowing that might be too obvious is announcing an event before it occurs. Like if this was a love story about if a struggling couple would get married, and the author foreshadows says something like "X booked the wedding at Naples", that's foreshadowing.
And now an example for something not foreshadowed enough; Like let's take the wedding example, and it ended with a phone call saying something like "I love your dog" and they just hang up, and the story ends. Like first, it was irrelevant, and second, that's not a cliffhanger or foreshadowing. So it's weak.
