A good tip on becoming more confident is to dress nicely and to practice good grooming habits. You need not wear expensive clothes, but you should wear clothing that looks presentable, and adds to your attractiveness. Combining this with proper hygiene e.g. taking a bath daily, brushing and flossing after meals, and so on, can help transform you from a person who's lacking in confidence, to one who's oozing in esteem or confidence. Getting a hair cut, a facial, and the like, are also techniques on improving self esteem that you should try.
To boost self confidence and also up your chances to reach your dreams, you should also remember to have good posture.
This means walking with your chin up, and with your shoulders and back straight. You should not think that only ramp models should do the thing wherein they walk back and forth with books on their heads. You should do that too as that is one way of practicing proper posture. Anyone who's lacking in confidence usually has poor posture, and so, if you want to start gaining confidence, start with how you carry yourself.
Another advice on improving self esteem is for you to think about the good things you have done for other people, or your contributions to society. Listing down those things will really help boost self confidence.
Even if other people don't remember the good things you have done, as long as you remember them, it will be easier for you to become more confident and be able to reach your dreams. If you fed a stray puppy, list that down. If you opened the door for an elderly person, be proud of that, too. Thinking of your positive contributions really does wonders if you are lacking in confidence.
Thinking positively or being an optimistic person can also help in improving self esteem. Do not be a pessimist. If you keep on putting yourself down or thinking that you won't be able to do what other people are able to do e.g. if others were able to ace the exams, you think that you won't be able to, then, the percentage of those negative thoughts happening is larger. For you to really reach your dreams, you have to think more positive thoughts than negative ones.
Follow these strategies and realize that it is not really that hard to boost self confidence once you set your mind to the task. People who are lacking in confidence should not feel that there is no hope because there is – confidence is not really genetic after all, it can be learned or improved.