How do you draw an apple realistically???

stick an apple up your hole

First draw a circle. Foughly sketch the details you want from the apple using the circle as a base shape. add a stem in the place you'd like it along with a line indicating the drop that you see in a apple near the stem. Lightly erase the lines and trace over the finalized sketch shape of the apple (You can expiriment around with the apples shape, make sure to outline the shape you see best after slightly lightening the sketch with your eraser).  Shade, Shading is very important because it helps define the details and add dimention. Try not to over blend. Make sure to also find your source of light, without it the shading and dimentions could look off.