The purpose of a Muslim’s life is to attain Allah swt’s pleasure.
To do this successfully, he has to act on the shariah completely.
The part of the shariah dealing with external acts of worship has been classified as fiqh. While the part dealing with internal states, character and actions is the subject of disscussion in tasawwuf.
In summary, acquisition and rectification of internal moral states (iklaq e batini) with adherence to external commands of Shariah is tasawwuf. These internal moral states form the basis of worship performed by our body. They include,
A. Acquisition of;
Love of Allah swt (muhabbat)
Abstinence (zuhud) , etc. and
B. Elimination or rectification;
Love of the worldly (hubb e dunyah)
Love of fame (hubb e jah)
Showing off (riya)
Calamities of Tongue: Lying (kazb), carrying tales (namemah), humiliating others, talking harshly & rudely, talking unnecessarily.
Envy and Hatred (hasad wa bugz wa keana)
Being stingy (bukhl)
Being spend-thrift (israf)
Greed (hirs), etc.
These basic concepts should be very clear in regards to tasawwuf.
Source = http://www.ashrafiya.com/about/