If somebody is blessing or cursing me, this will have effect according to the authority given to him over me by God. Parents, teacher, etc., people I did wrong, or myself, do have some authority over me.
An expression, which is less emotional then to curse is to commit. We commit ourselves easily to something like: “I will never have a baby”. 
Jesus can liberate me from such commitments and curses. Galatians 3,13 says, that he became a curse for us. A prayer together with another Christian is very helpful to get free. Jesus gave his disciples the authority to loose also curses: "I tell you the truth, whatever you bind on earth will be bound in heaven, and whatever you loose on earth will be loosed in heaven. (Matthew 18:18)
A good book, which deals thoroughly with this topic is:
Derek Prince Blessing or Curse: You Can Choose!

Luzius Schneider January 27. 2000