A method or plan we take in order to fulfill a need.
For example, order pizza might be one strategy you can take in order to fulfill a need for sustenance. Others might be cooking dinner or asking your parents for food.
A strategy can be conscious "I want to study in order to pass the test and feel appreciated". It can also be something you don't choose on a conscious level, but only act out without realizing or choosing it, e.g. someone who is afraid of heights might involuntarily freeze or have a panic attack if confronted with a cliff, as a convoluted attempt to achieve safety.