Many students ask how to develop an impressive personality that would help in career growth. I say, start from within; become a better person first.
Its easier to polish the outside, the dress code the makeover, the hairstyle, matching accessories, the sitting standing walking posture correction are all part of the external grooming. They are easy to pick up form a variety of sources. There are ready tips available for all these in various media too including the internet.
To develpo a great personality you have to start working with yourself, working on changing your thought patterns if they are harmful for you. Need to learn the right thinking process above anything else and then gradually other things follows. As a man think so does he become. Your current status in life is a resultant of your thought process over years. Mostly unknowingly many of us draw misfortune for ourselves getting into more depression and negativity and losing self esteem. Once you master your thoughts you gradually start becoming human and soon you are the master !