Unsettling Art - Tumblr Posts

Horror artist/expert side of tumblr, I have a question:

How would you go about drawing, or just making in general, an image (could be for a picture where a person is the anomaly or the environment is) where everything looks, like REALLY looks absolutely normal, like it could be a bright sunny day where everyone's outside, but something is just unsettling. Like in such a way that it would be difficult to the viewers to even pick apart why it's unsettling. But they just know something is off.

(Near) midnight doodles! Did the first one while listening to the gotg 3 score, and boy does that music go hard. John Murphy did GOOD

Text says: "Hello to you, too..."

“The Jester’s Children” (Ft. Ink Jester, aka I.J for short and 12 skele kids)

I used Tim Burton style on this drawing, looks both nice and eerie.