I've heard exercise is meant to be pretty good for improving self esteem.

I do deep breathing and self affirmations in my head especially when I think of negative thoughts-I am not that great at that but I think I am getting better at it with time.

Listen to yourself more.... notice what your thoughts are saying ?
respond with love and acknowledge them , be present :) with you :)

Believe in yourself, have faith in yourself, and know that you are just as important as the person standing next to you. Hugs GB

Focus on good things about yourself.
Every negative thought about yourself - stop yourself, mid-thought.
Replace it with something true, accurate and positive.
Re-word critical thoughts - even about things you want to change about yourself, in words you would use to tell a friend if she asked for constructive criticism.

I hope you like the quotes. I especially like the one by Lil Wayne.
======================================================
"Don't let other people's opinions distort your reality. Be true to yourself. Be bold in pursuing your dreams. Be unapologetically you!" Dr. Steve Marboli.

"Love me or hate me, I swear it won't make or break me." -Lil Wayne

Nutriton and exercise does help. I work in a stressful profession and sometimes wake up with low self-esteem and having a hard time getting up. When I have been eating right and working out, it helps.

That said, don't spend too much time on self-analysis. Instead, work on getting things done. Try to define some goals and take steps towards them. I have a family member who spends 90% of the time on analysis, 10% on action, when that should be reversed.
Start trying to take specific steps towards achieving goals, professional, personal, etc. Once things are done, you will find that you are proud of yourself.

Also try to be charitable and help other people. I am unfortunately not that organized nor do I have great people skills. Nonetheless, I am a good person and work on various food drives and other charitable programs. Even in tough times, it is comfortable to me knowing that I make a positive contribution to the world and ultimately that is what is important.

http://www.getselfhelp.co.uk/esteem.htm

Ive found this site useful, lots of printable work sheets.

I don't know if this works for other people, so far not for me, but my BF tells me all the time that I'm being too hard on myself. To try to be more forgiving and loving.
It's hard, especially if you've been treated badly, been put down, or the like.

I hope you can find ways to end the cycle for yourself. ((HUGS))

I agree about the exercise. Also, try things that you have never tried before and when you accomplish it, you will find your self esteem going up. Believing in yourself is a big factor. Only we can change how we see ourselves because in the end, we are the ones who live with ourselves. Also, try to take life more lightly, especially yourself. As I've heard said before:
I tried to be normal once
It was the worse 2 minutes of my life.
Hugs GB