Not being groomed
First impressions are lasting. Not being groomed and wearing ill fitted clothes makes you look like a guy who is simply not interested in looking good. Women place a lot of emphasis on appearances and that's the reason why they take so much care to dress well and look good. So take care that you wear well fitted clean clothes and get a shave or trim your facial hair before you approach a woman.
Not smelling nice
Smelling bad is offensive. Similarly dousing yourself in perfume can give the person around you a headache. And both, together, can be quite a put off. Before you head out to meet a woman make sure that you shower well and apply an appropriate amount of cologne. Don't overdo it!
Bragging
Bragging is seen as a very negative quality by women. Women today are as capable as men and also earn big bucks. Don't try to impress her by flashing your car or money as she can go out and get these on her own. What women want is for a person who is genuine and humble. Bragging certainly doesn't fit the bill that way.
Appear too desperate
The other extreme is to appear needy and desperate. A woman likes a man for being just that- a Man! By agreeing to everything that she says or by doing everything that she asks you to do, no matter how exaggerated, you look like a man who will do anything just to be with a woman. Take care of your self esteem and learn to put your foot down when required. You will find more women getting drawn to you this way.
Poor conversation skills
Not being able to manipulate or build a conversation, not letting her speak or not listening to her when she does all make up poor conversation skills. And there can be no greater turn off than a man who does not know how and when to speak and to listen.