To boost your self-esteem, you need to identify the negative beliefs you have about yourself, then challenge them.
You may tell yourself you're "too stupid" to apply for a new job, for example, or that "nobody cares" about you.
Start to note these negative thoughts and write them on a piece of paper or in a diary. Ask yourself when you first started to think these thoughts.
Next, start to write some evidence that challenges these negative beliefs, such as, "I'm really good at cryptic crosswords" or "My sister calls for a chat every week".
Write down other positive things about yourself, such as "I'm thoughtful" or "I'm a great cook" or "I'm someone that others trust".
Also write some good things that other people say about you.
Aim to have at least 5 positive things on your list and add to it regularly. Then put your list somewhere you can see it. That way, you can keep reminding yourself that you're OK.