Interesting that they actually told you.
The unfortunate thing for a man is you have to decipher what their coded language means. the whole "too quiet" means you haven't displayed alpha male traits in front of her. Women wan't to see that other women want to be with you. As trivial as that may sound, that is a main part of a woman's attraction to you. This can be displayed without you showing off anther woman in front of her. Females can pick up much quicker than males on how at ease you are with yourself. Your self esteem oozes through the first words you speak to her and also your body language before you even speak.
Many in this thread have mentioned working on yourself and forget about doing things with the sole intention of pleasing a woman. That will be your main way of becoming more "attractive". Females want to be apart of something that in some sense is bigger than themselves. When they see that you are focused on whatever it is and you're not going to be thrown off by their antics, that builds attraction. At the same time, you have to put yourself around more women. If you're being told you're "too quiet", you're probably not expressing your inner self freely around them.
Females are all over the place in their thoughts which is why they like spontaneous actions and being in the moment. As a man, you can learn to step foot in that world without becoming attached to it. It does take some time, but once you get the experience you can pop in and out of state at will. That is essentially what "bad boys" are doing and why women find them irresistible.
http://www.amazon.com/Way-Superior-Man-Spiritual-Challenges/dp/1591792576/ref=sr_1_fkmr0_1?ie=UTF8&qid=1422848899&sr=8-1-fkmr0&keywords=dan deida
This book "The Way of the Superior Man" explains most of this in detail. You can also find the same teachings in various religious texts, but you have to have a open mind.