Depends if you are using a powder/cream contouring product. With cream you can really get a sharp/chisellled look, if you want to use a cream but have it look more natural you can start with less product and use a beauty blender to blend it out. I find powder contour to be much easier and look more natural, I apply it with a brush and carry on blending until there’s no harsh lines. You could also try applying it before your actual face setting powder which will also make it look really natural and blended x
I would say make sure you find the right shade for your skin type, if your light you need a more of a grey based contour, and if you have warmer skin you need more of a warmer base, also if your using brushes i always find that a fluffy angle brush will do the trick, the best placement will be the hollows of your cheeks by your ears, and you can always blend out any harshness with your face powder you use to set set your face with to look more seamless.
Powder contour lends itself to a more natural, less heavy look than cream contour, but whichever you use, I find the best way to make it look more natural is applying only a little product at a time and building it up until you get the desired result. After you’ve applied your contour you could dust in some setting powder or pressed powder to diffuse the look of the contouring. Good luck!