A person with low self-esteem will be more persuadable than a person with high self-esteem when the advocated message is weak. Notice the important qualifier: "...when the advocated message is weak." There's no simple linear relationship between self-esteem and persuasion (William McGuire1969). So it is a important countermeasure to keep or build your self esteem up. Here are a few links to help you.

First Cult Influence tactics
http://www.excultworld.com/misc_articles/kelton%20rhoades.htm

What is self esteem? and improving it
http://www.utexas.edu/student/cmhc/booklets/selfesteem/selfest.html

3 Faces of Low Self-Esteem

Consequences of Low Self-Esteem

Three Steps to Better Self-Esteem

Further Resources for Change

Self-esteem - Wikipedia, the free encyclopedia

1 Measurement
2 Quality and level of self-esteem
3 Issues
4 Self-esteem, grades and relationships
5 Bullying, violence and murder
6 Self-esteem and economic motivation
7 See also
8 References
9 External links

Changing Your Self-Concept and Building Self-Esteem - Psychological Self-Help

Activities That Will Help You Feel Good About Yourself
http://www.mentalhealth.samhsa.gov/publications/allpubs/SMA-3715/activities.asp

Article: Building Self Esteem
http://www.mentalhealthrecovery.com/art_selfesteem.html

Building Self-esteem A self-help guide
http://www.mentalhealth.samhsa.gov/publications/allpubs/SMA-3715/activities.asp

Building Self-esteem
A Self-Help Guide
http://www.mentalhealth.samhsa.gov/publications/allpubs/SMA-3715/introduction.asp

Things You Can Do Right Away—Every Day—to Raise Your Self-esteem
http://www.mentalhealth.samhsa.gov/publications/allpubs/SMA-3715/things.asp

Changing Negative Thoughts About Yourself to Positive Ones
http://www.mentalhealth.samhsa.gov/publications/allpubs/SMA-3715/changing.asp

Self Improvement and Building Self Confidence Information

What is self esteem and how can you improve it
Counseling To Enhance Self-Esteem
Self-Esteem and Narcissism: Implications for Practice
A Buddhist View on Lack of Self-confidence
Exploding the Self Esteem Myth - Scientific American
Articles, tips, and activities on how to build your confidence and self esteem in your work and personal relationships
Self-Esteem and emotional well-being articles for Teens
The costs and causes of low self-esteem
Thymos, Dignity & Self-esteem