1. You don't need him. When you make a man feel needed, when you let him do little things for you, it taps into a primitive part of his brain (the hunter and provider part). It makes him feel like a man, it makes him feel happy and it increases his attraction to you. Many of the women I see are very capable; they can change tyres, do the decorating and hold down a demanding job. This is very commendable but any man coming into their lives won't feel needed. So when a guy you like is around, ask him to do some of these things, "honey, can you fix the taps?" or at the least, if he offers, let him do these things, right from the beginning of your relationship.
2. You hide your warmth. Some women have turned off their inner warmth, their inner sparkle, to avoid attention at work. When you sit in front of a computer screen all day there is also no incentive to sparkle because it doesn't sparkle back! Women can forget to switch their emotional side (the fun, playful, relaxed, sparkling side) back on at the end of the day or when they meet a guy they like. If you radiate warmth you're much more likely to receive it and become irresistible to men.
3. You don't show appreciation. When men do something for you, acknowledge it, smile and say thank you. Men like to feel appreciated, so say thank you and give a reason why. "I really like that because you've saved me so much time; it's too heavy for me" etc. When they know the reason why and they know exactly what they did to please you they'll want to do it more often.
4. You don't show your emotions. To survive at work many women develop a shield or a wall and avoid being open or showing any vulnerability. This can be unattractive to men and make you seem distant. When you feel the need to be strong at work all day sometimes you can forget to let your guard down. Men are programmed to fall in love with women who show vulnerability. If you're always waiting for the other person to show love or trust first, it can become a battle and nobody shows any emotion and nothing ever happens. Be open to love and letting a man know that you're interested.
5. You're on a mission to find a man. Many women I meet have been focused for a long time on their career, and suddenly realise that time is passing and they need to meet someone. They then go on a mission to find a man, which can be very off-putting to potential partners. Having a defined set of expectations and a time-frame can also be counterproductive; no man wants to feel he's on a schedule. The more relaxed you are dating, the more attractive you are to men.