To have confidence in your ability to do something is known as Self-Confidence. Self-Confidence is very important in our daily life activities. To gain self-confidence there are some ways .
Determine your qualities, traits and abilities. Whenever there is something which you find difficult to do you must remember your qualities and abilities so you realize that apart from difficulties and problems , Allah has gifted you with many abilities and if you try you can do this specific thing as well. Discover your talent and spend much time focusing in that because Allah has gifted you with that specific thing for a specific reason.
Don't become jealous of others. If you want yourself to become self-confident don't compare yourself with other people or some people you envy. Apart from making your life better it will make it miserable. Learn to forgive others and also yourself. If someone is better than you at some point try hard but don't start to envy. None of the persons in the world are good at the same things. If someone is good at weight-lifting you can be a good runner , it isn't necessary to be the other person.
Smiling , working hard and respecting other people helps you gain self-confidence. Accept other compliments thankfully because they are noticing you. Don't be a selfish. No one loves selfish, Be a winner. Help others , believe in yourself and you will be a much self-confident person.