While children aren't delivered with a "how to" manual, there are several great resources for parents, such as Larry Steinberg's 10 Basic Principles of Good Parenting. Steinberg recommends a number of ways to show your children you love them. For example, shower them with affection. There's no such thing as being "too loving." Even teenagers benefit from this; no research has yet found praising and hugging to be harmful to teenagers!
Another way to show you love your children is to consistently guide their behavior using effective discipline and by modeling good behavior. How you walk, not talk, makes the difference. Research consistently shows that from young children to teens, youth imitate by example, not by what is told them without follow-through. In the presense of children, your actions matter.
Set loving limits on your child. Firm but fair rules and consequences for breaking rules need to be set in place. Most important, following through on consequences without compromising gives children a sense of boundaries and safety.
Be consistent, but not rigid with your child's schedule. Keep in mind areas that are non-negotiable. Have a set schedule for weekdays and weekend, yet be a bit flexible, including time for recreational activities and leisure.
Stay involved in your child's life. The definition of involvement changes as they age, but the amount of involvement in your child's life should not change. For example, most adolescents don't need micromanagement, but they do need monitoring. Some teens need a lot of monitoring!
Parenting can be one of the toughest, yet most rewarding and most important jobs you will ever have, with results that last far beyond your lifetime.