Question: what to say to someone with low self esteem?
Answer: Don't engage in, or encourage negative image conversations. No bad thoughts! ... 
Tell them you love them and why. ... 
Actively share positive things with them. ... 
Encourage self-care. ... 
Be caring, but be firm. ... 
Don't tell them how to feel. ... 
Help them change their focus. ... 
Give them a challenge to conquer.