Take a look at following Diagram:
Understand which house represents what relationship – it will help you in your readings.
So, in simpler terms for predictions if your 8th house is spoiled – Relation with your in-laws will be in trouble.
*** Note that Father is included for Both 9th house and 10th House. Some Books consider 10th house for readings of Father – Some 9h house. You choose what’s best for you.