If you think of the last time you were angry- you might want to visualize that situation in your mind. Now look at where exactly anger felt- is it in the head, the throat or heart area? Can you give this emotion a 'shape'- where/how it is spread out? Now this is the likely place where you will feel most other defilements. Now there can be concommitant thoughts as well (ie angry thoughts in this case). You can just think the thought 'I am a strawberry' and see where you might feel that- usually somewhere in your head. Defiled thoughts would arise there. This is the way that even wholesome mental states can be directly detected in your mind/heart.