ah...... O_o
Give youself a little bit more of a challenge. I can't give you any advice on a simple "perfect rounded" apple.
For your lighting:
first, turn off your ambien light (or the default light) overall looks too bright.
In an image, you want to have a focal point. You want to let your audiance able to define this is an 3D object that has weight on it. Over saturation isn't a good idea.
Try to lit an real apple in real word. Turn off all the lights in the room, put only an apple on a table or whatever, bring 1-3 spot lights. (i don't have a spot light in my house. i usually just use my table lights. and i usually get 3 of them)
What you are looking for is a focal area, shadow area, and the highlight on the edge.
Focal(diffuse) area: You can create your own. stair at the apple. get a feelin for it. than ask yourself. which part of it is the most beautiful, and i want to show that. For me, i would choose the skin of an apple, since the whole surface of an apple is skin then i sould just pick one spot of it. Which spot you ask. well, it is base on your idea.
Shadow area: which we call ambian. not the real hard shadow that the apple creates, is the ambian colour of the apple where the main light can't cast on to. You don't want it tobe completely dark do you. well, you can, i mean as long as it looks cool. But if the apple only showing the focal(diffuse) spot, that will be boring.
Ambian area usually appears on the opposite of the diffuse area. But keep in mind that you don't lit it too bright. you want your audience to understand this is the ambian part. Usually what i do is either case a dark blue light on the opposite side of the main light. or case the opposite colour of the main light. it depence onthe situation.
Highlight: I don't usually do a hightlihgt, because i dont' like the edge glowing. but this is how you do, cast a light from the back of the apple, so that it makes the edge glow. play around the position and see which area is the best to show the edge.
Usually i'll do it without reference. But it always is a good idea to pre-lit in real world first. i am jsut lazy
