Put that in the back of the net

Goals help individuals to direct it towards achievement
Goals encourage strategies to ensure achievement
Goals help build assistance required for achievement
Goals encourage new learning strategies to ensure achievement
Goals that are more specific are more achievable than generalized goals (.eg to be the best , or to be good)
Goals are within the individual's control and thus are flexible
Goals set more realistic expectations resulting in less anxiety and more motivation and thus enhanced performance.

Goals Should be:
Specific, Measurable, Behavioural
Challenging but realistic

Explicit goals are far superior to general non-specific goals, such as 'must do the better'
The more difficult the goal the better the performance but unrealistic goals beyond the individual ability leads to frustration and failure. Consequently goals must be difficult  enough to challenge but realistic enough to be possible