Its not so much as psychic, its more psychological.
For example, when two basketball teams were seperated, one told to practice for 1 hour, the other told to visualise sucess, the visualising team did better (improved 35%, compared to the first team which improved 15%).
It depends on your beliefs, but from a pure scientific view, "psychics" often use vague language in order to avoid any absolutes. Using psychic stuff on YOURSELF will only have a psychological impact; as you believe, you will be.
However, if you do intend to use this sort of stuff, be careful of excessive failure. Failing too many times when using a "belief" can often drive people into psychological depression. Don't forget that belief often blinds people; Hitler for example believed it was the German soldiers who had failed him, forgetting to analyse his own military mistakes.