Your image plays a big role in attracting a woman, so it's wise to think about your personal style. It does not have to be a certain specific style out of some expensive magazine, but rather dressing yourself well in a way that reflects well who you are and what you're into. What this means is that the same dingy shirt and pair of jeans is NOT style. And you don't have to be "stylish" either, or have to spend a lot of money. Your personal image and style are not necessarily correlated to an expensive price tag; the key is to dress decently in a way that reflects your best self.
Wearing clothes that really brings out your best features (and gets you compliments) also helps boost your confidence. You'll notice that you start to receive better treatment and higher measure of respect. It may seem unfair for people to equate your style of dressing with how you must be as a person and what your background must be like. But as your outer image is the fastest and frequent way that you can convey your inner image to the world, so people correlate - rightly or wrongly - your image and style for who you are. For instance: a man who only wears torn and dirty jeans with t-shirts and a baseball hat will receive one type of treatment, while another man in a clean and pressed dress shirt with nice slacks and clean shoes, will receive a completely different treatment.
In the process of developing your own image and style, be adventurous and open to possibilities. If you're just starting out or would like to make a change, remember: doing anything new requires an openness to change. Don't be intimidated to try some clothing you've never tried on before. Set aside preconceived notions, and experiment. I remember watching a program where a man said that he felt intimidated by suits as they required a refined style that he didn't. He felt he "wouldn't be comfortable wearing them, as his 'style' was to wear jeans". Well, this is not to say that you can't look decent wearing jeans, but with all due respect to him, saying that it's too sophisticated for him is nothing more than a resistance to change. As Will Smith says in "Hitch", in developing your style to attract women, "the YOU is a fluid concept" and can be molded to give you the results you're looking for. Removing these preconceived beliefs is important, to get the benefit from developing a style that reflects your best self well. If you want to attract women, understand that women appreciate men who are well-dressed. Well-dressed men turn their heads, so start using style to your advantage.
Different fashion "experts" will have different opinions of course, but for starters on style, here are some tips:
A general rule of thumb is to NOT mix patterns together as it can get too busy, especially if they have different colors. If you are going to wear a shirt that has a pattern on it, then make sure that it's the only pattern that you will wear. This means that your pants should have a solid color (black or grey is typically the safest with any color). If you have a pair of slacks that have any type of pattern on them (like pinstripes) then make sure that your shirt has a solid color.
Some men make the mistake of wearing a suit jacket over a t-shirt or another type of collarless shirt and jeans- DON'T DO IT!! For most men, it is definitely not a flattering look. Unless you're a movie star or mega-millionaire with women on each arm and couldn't care less, the whole combination gives the impression that you don't know how to dress. Either remove the suit jacket and go for a casual look with a sports jacket or if you want to look a bit dressier but not overly so, then wear a dress shirt without a tie or a suit jacket accompanied by a nice pair of slacks. That's it - simple.
Along with being tidy and wearing items that you enjoy as part of your ensemble, try a bit of color. Men typically don't use a lot of color in clothes, but a bit of color can really compliment your look. You can augment your style with pieces that have colors that you like. Some power suit wearers for a while now have been broadcasting their confident style with salmon and pink - yes pink - I have seen some guys wear it and they look fantastic, especially if they're Caucasian. If you are of African descent then go for darker shades; the same applies to Hispanics and Asians.
As you grow more and more into your own personal "style", you can move on from the basic to an even more sophisticated look. Image consultants will be useful if you can afford it. Style and image magazines can help - but what's important is that you find the combinations that work for YOU, make YOU feel good, get YOU better treatment (and compliments), but best of all, attract women into your life. All the best!