Im going to say something which is pretty much in line with what others have said. Not because its any more accurate but because it may shed a bit more light on the topic.
There is a sutta (Historical record of what the Buddha said) were the Buddha talks about identifying what is not self (annata). He directs the attention of his student towards five categories. These five categories divide up all the components of our unfolding experience. Here are the categories:
This is the subjective texture of experience. It could be further divided into the types of sensation or elements of experience like hardness, Fluidity, motion, heat, etc etc.
This is the preferential tones which accompany experience. They fall into three categories: Pleasant, Painful, and Neither Pleasant not Painful.
This is the identifying at every level which picks out particular details of and interprets experience.
This is a hard one to get at but in this context I think its best understood as volitional predispositions in action.
This is the objectifying aspect of attention which is constantly projecting a subject in relation to an object.
The Buddha points out that if these components don't meet certain criteria they should not be regarded as a self. So he is asking us to systematically look into our experience using the categories above to see if they meet these criteria. That way we will begin to have a more appropriate understanding of how to regard our experience.
These criteria are:
1) It is not conducive to dis-ease.
2) We are able to will it to be as we wish it to be.
3) It is constant or without fluctuation.
We look into these five aspects of experience and we find that they are not constant and that we cannot consistently will them to be as we like. In short they are conducive to dis-ease and it is not appropriate to regard any part or combination of them as a self. When we begin to see this clearly we will become ever more calm, patient, kind, and compassionate. We will become disenchanted with any goals other than those connected with releasing beings from suffering and stress.
This is all from the Anatta-lakkhana Sutta
I hope it helps
"Beautifully taught is the Lord's Dhamma, immediately apparent, timeless, of the nature of a personal invitation, progressive, to be attained by the wise, each for himself." Anguttara Nikaya V.332