The reason why we don't attract the people we desire (eg. romantic partners) is because we are not "in tune" with them. What does this mean? It means that when we are angry, disagreeable, critical, and competitive we tend to attract partners with the same characteristics. You see, "birds of a feather flock together", meaning that similar people tend to associate with each other. Thus, what you attract in your life reflects something in yourself. You may like this "part" of yours or not; furthermore, you may even be unaware of its existence, as you probably have been hiding it for a long time. Yet, it manifests in the people you come across (the reason being to help you gain greater awareness, so that you can learn how to deal with it, grow as a person, and move forward).
Therefore, if we wish to meet kind, caring, enthusiastic, attractive people in our lives we should cultivate and develop those qualities in ourselves first. By doing so, we will "stay in tune" with the people we are looking for. Secondly, according to the "law of attraction", we should employ our imagination to visualize the desired situation we seek out. For example, we can visualize ourselves living moments of happiness with our ideal partner. How would you like him or her to look like? How are you going to spend your time together? What activities could you do? What qualities would you like your partner to possess? You may answer these questions and then let yourself relax and enjoy your dream.
When visualizing the moments you wish to live with your partner, remember to remain non-judgmental! This is in fact, very important! It implies that, If you start criticizing yourself ("I am not enough rich, beautiful, slim, tall, educated, lucky etc... to achieve what I want") or doubting the possibility of success ("It's not going to happen to me..."), you infuse negativity into your thoughts and your emotional (vibrational) system, thus obstructing the good things to enter your life. Therefore, just stick to your dreams and avoid judgment and criticism.
Finally, start working on your goals! Personal development, visualization and action are all of equal importance! Do not expect that your dreams will come true without effort... Develop some sort of a "personal plan of attraction"! Decide, what kind of a person you wish to attract and what steps you are going to take. For instance, maintaining a healthy lifestyle and working out will improve both your body and your confidence. In addition, to meet the right person it might be helpful to enrich your social life. Consider starting a new hobby or social activity, accepting social invitations, joining groups related to your interests and so on. And always remember: Be clear about what you want and stay positive!