Confidence is a belief within yourself that you have the ability to do something that you want to achieve. So you need to boost confidence. Like if someone have the inner feeling that they can do some task smaller or bigger they need to have some actions in order to fulfill it by breaking into small achievable units than to overestimating the ability to do large task in shorter period of time or putting less effort which is required.
Confidence is built by affirming the will you have to do something even if somebody criticizes you or does not believe in your ability to perform still you perform it and achieve it and prove yourself and certainly built your confidence level.
1-Under-Confident or Over-Confident
Confidence has some aspects like you maybe under-confident or over-confident it depends over your thinking. The more your thoughts strong about any matter it’s likelihood you are going to behave that way.
For instance if you can perform some task you have already learned and you hesitate performing. You do not belief in your ability to do it you are under-confident whereas if you lack some ability or you does not take time for a larger task and yet you do not achieve it you are over-confident.
2-Learn from Mistakes
Nobody is perfect everyone makes mistake but learning is the key aspect to build your confidence level. One of the best things you can take out of mistake and if someone criticizes you instead of feeling low take steps to correct yourself and learn from your mistakes and boost confidence.
3-Keep away from Negative People
On the other hand keep away from negative people or who make you feel bad about yourself. It is better to surround yourself with positive and encouraging people. You should also mentor others if you know something in return you it will boost confident.
Ways to boost Confidence
The idea behind to improve confidence is to feel good about yourself about your tasks with a knowledge you possess or you have to learn make it to the point of implementation and get things done.

1-Planning and preparation
Planning and preparation is for the unseen that at your position you need to be prepared for a certain event coming in the future and sometimes you have a backup plan for that and if something fails you are not in panic but calm. This boost confidence.
For example, you are going for an interview you might visit their website or prepare what you would like to ask, or you are going for travelling and you prepare everything early so that while traveling if you require something it should be available.
2-Learning, knowledge and training
Learning from different sources is a great way to increase knowledge and boost confidence. When you gain knowledge or undergo some training you have the ability to perform well which ultimately makes you confident. But it sometimes makes you less confident at that time you need to combine your own experience to get the task done.
For example in an organization employees are required to undergo training to perform better which most people resist as change feels uncomfortable but it will add to your benefit and makes you do task more efficiently. The other example could be for a first time parent to be you search a lot how to take care of your child even you ask other parents who have already gone through this.
3-Stay away from negative and bring on the positive
In your surrounding there are your friends and family. There could be chances that some of them when you are around they behave negatively or they might do something that shred your confidence. The best way is to cut off with them or be distant to them so that their negativity should not affect your mood or the way you feel about yourself.
There could be some circumstances where you are stuck in then instead of just focusing on problem take steps for some new project. Do what you feel you are good at. Keep on doing something instead of wasting time doing nothing or unproductive tasks.
4-Change your body language and image
A smile on your face, an eye-contact and straight shoulders makes your posture seem to be of a more confident person. You feel good about yourself and others perceive you confident and it also make them comfortable when they are around you. The other thing that counts is you speak slowly which is understandable and yet is conveyed better and you are portrayed confident.
For this what you can do is go to a hairdresser get your hair trimmed, shave your beard, dress nicely which makes you feel good about your appearance and people also appreciate a self-caring person and it will make you feel confident.
5-When you fail challenge yourself
When you fail never give up. Do it again and see or ask someone where you lack or analyze yourself where you are mistaken and correct yourself. Instead of saying to yourself I am not good enough, I can’t do well, it’s difficult or I would do some other time and you neglect.
All this what you are telling yourself is stuck in your head and makes you feel that way and you feel you are a looser and if you continue doing it you don’t learn enough things to perform better. Making mistake is not wrong but to correct it immediately is the requirement.
6-For tough times create a great list
Life is full of challenges sometimes some situations might feel you under-confident about yourself. At that time make a list of things you have accomplished, or where you are good at, what things you are blessed with for which you are thankful for. Paste it on refrigerator or wall where you can recheck and tell yourself that you are better in many things and you can do better in your future.
Conclusion
Life is all about ups and downs. You need to keep on learning with recognizing the ability you have and perform it well with smaller steps regularly. It will boost confidence and will benefit you in future when you recall that despite of problems I have overcome by focusing on my tasks.