Identifying Sin

A sin can be defined as something that is 'unjust' to your soul. The problem is how do you know when you are being unjust? How can you tell? And how can you stop? How do you identify sin? How can you become aware of sin? How do you know when you are committing sin? I have began to identify the following factors to identify sin.

• A feeling of guit 
• Uncomfortableness in a situation
• A feeling of wanting to make Tawbah (repentence)
• Excess enjoyment in material pleasures
• Imitation of disbelievers

What if you have none of the feelings aboove? Or are not aware of the other factors suggested?
I have noticed that in order to identify sin you have to want to identify it, or at least be aware of your motive for a particular behaviour. An important lesson I am learning, is the more knowledge I seek, the more I will learn, and the more sin I can identify to make tawbah for and rectify Inshallah.