I have zero concentration cant focus on what am doing always thinking with other things when i am working. .. how to enhance my concentration ?

Needs assessment: There are many issues which can interfere with concentration: medical or psychiatric conditions, life circumstances, medication, et al. Someone taking careful history from you - date of onset, correlation with any of the above issues, family history - can further define the cause and help in its management. I would suggest consulting an MD or psychologist to help pin down the diagnosis.