How can I develop self confidence and self-esteem?

Invest in yourself.

The best way to improve self respect is by being deaf to negative criticism thrown at you, and doing whatever you want to do as your heart desires and succeed to prove your detractors wrong. Nothing improves your respect than proving your critics wrong.

I wrote a bunch, then finally some good stuff started pouring out (haha), so I copied what is like a very "chicken-soup" conclusion...here ->   So finally, it appears to me, and has for sometime, that self-worth is driven from the inside. And there is no better time to recognize how awesome you are than right now because you are one of a kind...no one else is like you, thinks like you, dreams like you, has an imagination like you, loves like you. So it's really in what makes you "you" from which you can try to run but will never really make it far, and shouldn't ever catch yourself doing in the first place, that gives you automatic worth. If you abandon your instincts, feelings, desires, free will, for other people's attention and other people's approval and generally empty time, you will end up wasting time in getting to know yourself. You won't know what to do with your freetime, you won't be confident in your own feelings and be able to make your own decisions. You gotta embrace yourself. Your body is a vehicle through which you experience life. Do you want to live the life that reflects you, or just do what other people expect of you? Think of self-worth like it's an on/off switch. You just wake up and you do it. Keep doing it, dive in, do what you feel like, be honest with yourself, and I guarantee it's like feeling brand new but super wise at the same time. No one knows how to live "you" like you do, but you got to believe in the value of your own ideas/thoughts/decisions.   I think we naturally develop an opinion of ourselves starting at a very young age. And most of that development is driven by the perception of ourselves through other people's opinions, direct/indirect/irrelevant, about us. The first line of development outside of our own self-reflection, which generally happens later in life or during "down-n-out" periods of our lives when we confront our lack of self worth and seek help in literature/friends/etc, as an active pursuant of this worth that has largely been an accidental development most of our lives, is our parents. Soon after it becomes our peers and our biological instinct to seek acceptance starts controlling our actions and we more or less do what other people expect of us for a while until we either just naturally drift towards a life that is an actual reflection of who we are or a life that we feel lost in.

The first step is not to worry how others might react to it. Freedom of speech is the key towards being confident. Being around a superior crowd is also a major part of it. When I was growing up I was one of the slowest kids of my class who everybody picked on. Today I'm one of the most successful of my class. It all came with perseverance and clear focus. Never fear the outcome, do what you feel and it will help majorly.

Self confidence is a belief in ones own ability to accomplish a task. The most surefire way to enhance that belief is to get out there and do stuff! Find things that you enjoy but still find challenging. If you're athletic, find a sport. If you're a thinker, find mental challenges primarily. Mix it up and get into things that you don't consider your strong suit to keep a balance. Turn a weakness into a strength. Soon you will exude a confidence based on experience and not puffery.

Know that every one else is like you. You are not better than any one and worse than any one. You are one among everyone.

How to build your creative confidence? http://www.everscoop.com/article/how-to-build-your-creative-confidence/

Start doing things. Do things that you like, Wear clothes you want to, say things you feel like saying, talk to everyone loud n clear !

Here's the thing about bullying and why you cannot trust others' opinions of you... the reason being is that it's almost always not what it seems. This is more clinical but just as valid: "Psychological projection is the act or technique of defending oneself against unpleasant impulses by denying their existence in oneself, while attributing them to others. For example, a person who is rude may constantly accuse other people of being rude. Although rooted in early developmental stages, and classed by George Eman Vaillant as an immature defense, the projection of one's negative qualities onto others on a small scale is nevertheless a common process in everyday life." "Freud considered that in projection thoughts, motivations, desires, and feelings that cannot be accepted as one's own are dealt with by being placed in the outside world and attributed to someone else." "Bullying: A bully may project his/her own feelings of vulnerability onto the target(s) of the bullying activity. Despite the fact that a bully's typically denigrating activities are aimed at the bully's targets, the true source of such negativity is ultimately almost always found in the bully's own sense of personal insecurity and/or vulnerability." So you see what is going on psychologically? Really, all the negative things that they say about you, are really subconscious feelings that they feel about themselves. For example, they may feel unattractive/ugly. Rather than face that, or worse, rather someone else notice this about them, they distract attention away from themselves by focusing the attention on you by literally calling you out. Making a scene of it. That assures you're the focus of the observers and while everyone is focused on you, they can't be focused on how unattractive the bully is! Pure distraction. This is ages old, this psychological concept / defense mechanism. The worst thing you could do is ACCEPT their criticisms (just superficially, not take them seriously). As its said, what can your enemies shoot you with if you hold all of the bullets? Meaning, if someone says something to get to you, to hurt you— and you don't let it affect you (pretend if you have to at first)... then what? "You're fat!" -"Ok? And? You're a bitch for pointing that out. Plus, you're not exactly the skinniest thing either, I don't know if you think that or something? I'd lose a few pounds before calling someone else fat." - "You're disgusting." - "Really?! What are you, 12? Grow up." It's immature and it's playing at their low level but sometimes you've just got to fight fire with fire. Psychologically, the two most effective things you can do to them in the case of comments / bullying would be to: A) be completely unaffected or unconcerned with their thoughts and opinions... because you shouldn't be anyways. There's something called subjective reality/perception. What one person thinks does NOT make it a universal truth. It makes it their opinion and only their opinion. If their buddies agree, it's because they're confirming and fear being the one to go against the group. Sheep. They back each other up because they're insecure to just let the statements stand for themselves without peer approval "yeah yeah heh they're right". Cowards in a group are less cowardly because they band together and back each others' BS up. B) reflect that diverted attention right back onto them. Reverse what they're aiming to do. They want the focus on you. Take that power away from them and put THEM in the focus, especially a focus that is intimidating or embarassing. Once you embarrass them a good couple of times they will learn 1- I screw with her 2- she embarrasses me 3- I don't want to provoke my own embarassment, so I'm not screwing with her! Think it out ahead of time. If there's a specific person always making similar comments to you, pick something that's not so perfect about them and when they comment on you, embarass them by pointing out their flaws. Eye for an eye isn't always the solution, but these things will quickly end their antagonism if done effectively. Don't take their s***. If they insult you first, throw one right back They rely on your being passive and taking it. If they learn there will be a response that is unfavorable to their own self confidence or image, they will learn to cease the behavior, which is opening their mouth towards you. Then they will be negatively reinforced by the aversion of your counter-reaction. Those are fundamental things, they're so basic, but as said, if you can make them feel humiliated each time they do it to you, they'll stop because they'll know you will respond in kind. Failing all, simply TOTALLY IGNORE them. Don't look at them, hear them; they don't exist. They're looking for a REACTION from you. If you stop providing any show of any reaction to their actions, it makes them pretty pointless after a bit.