Determine if the freedom is a freedom to do something or a freedom from something. If a certain rule or structure enables you to reach your potential, that is positive freedom. For example, rules about perfect diving form inhibit your ability to play in the water but free you from childishness and allow you to reach your potential, which is positive freedom. Conversely, the absence of rules governing diving behavior maximizes negative freedom.
Consider the agents involved. Ask if the core freedom is personal or if it involves others. For example, negative freedom rules say that you can drive your car at any speed on your own property as long as no one else is near enough to get injured. Proponents of positive freedom, however, would suggest that your desire to drive fast would be better served by learning the rules of safe racing and joining a racing team. External rules would free you from your own impulsivity and allow you to reach your potential.
Focus on barriers and actions to distinguish between positive and negative freedoms. Understand that they are interrelated, so a single act can impact freedom in both a negative and a positive way for different people. For example, smoking is a positive freedom for the smoker and barrier reducing negative freedom for the Asthmatic.
Examine the role of society and rules. Proponents of negative freedom argue that rules restrict freedom for a least some people, but supporters of positive freedom often feel that mutually agreed on rules allow people to reach their potential which is positive freedom. Remember that in real situations this can get complicated. For example, freedom of religion is a negative freedom because you are free from barriers to your religious expression. However in 2001 a German case was heard in which a Muslim teacher was asked to remove her head scarf because it was seen as proselytising, making it a barrier to her students' comfort with their own religions and thus a constraint to negative freedom.