Hackers

Privacy has been a major issue with my online experiences lately. My myspace blog has been hacked into numerous times. I have had blog entries deleted from that particular blog as well as other issues. It has gotten to the point where I log into myspace and there are minor alterations to my page like changing my height that let me know that my account has been hacked yet again. I change my password very frequently....How does one prevent this from happening? Is it possible to prevent hackers from getting into online accounts?