If you want to pick up women or just impress them as a starting point, it is absolutely essential to dress well. Women will take interest in a well-dressed man over a shabbily dressed one any day of the week. It says a hell of a lot about you to the outside world if you have bothered to take even a tiny bit of pride in your appearance. And the ladies will love you for it..
Make sure you dress for the occasion. A shopping trip doesn’t require a tuxedo and a first date at a nice restaurant will not work out if you are wearing a battered t-shirt and shorts. Some say it is better to over dress than under dress. There is merit in this but I would try to do the research first. Think about what you have seen others wear in similar situation and work around that. If in doubt, your semi-casual chinos, shirt, jacket combo rarely fails.
Project the image that you know about fashion, that you have an idea of the latest collar style or leg cut. Your clothes do not have to be really expensive or from a designer label, they just have to be fairly new and chosen in a style that works for you. You will score a lot more points if you can show you put some thought into what you are wearing. Being well dressed is more about choosing things that suit you than going for super expensive, rock star clothes. You know what it looks like to see someone who is over dressed and the only way they decided on their wardrobe was by the price tags. It looks tacky. Think about things like, if you are a little overweight then watch the tight fitting numbers, if your body is a bit short watch tucking your shirt in your trousers. Look at the models that companies like GAP choose. Some of these are going to be as close to average Joe’s as you will get and they look great.