Like the image above with the young man holding the phone. It looks fine until you see the phone he's holding and against his arm. Two different colors contrasting. But the darker colors like his shirt and the rest of the image just blend making it harder to see the outlines of things. Makes the image look nice and smooth overall or what we're used to seeing when uploading to Instagram. So it may be the combination of a Samsung S4 thing and high megapixel count.
And surprisingly, the photo looks really good when view on instagram, using the overly saturated S4 screen.
Anyway, most probably best bet would be to make bunch of photos and different styles and find out first hand which one comes out on Instagram the best. Just like regular photography, when doing photos in the morning produce better results than noon, with a very washed out sky.
Find out the sweet spot, and keep that in mind when taking the next shot