One thing you need to be aware of, once you begin your role as a step father or step mother, is that you need to go slowly when you first begin. It's often a painful adjustment for kids, who may have recently lost a parent, through either death or divorce, recently. Step children may find it very difficult to accept you at first, especially dependent upon the way they lost the other parent.
Basically, how old your stepchildren are will determine how you interact with them. It's easier if the child or children are infants or toddlers because they will grow up considering you their natural parent. You have to be prepared for this responsibility when you get involved in such a situation. It's not unusual for someone who becomes a step-parent to older children to become their companion and mentor more so than their parent. The original parent of teen-aged stepchildren in any new marriage will most likely be the primary parent with the stepparent assuming a supporting role. To be sure, each family faced with these same circumstances will have different needs, but the age of the stepchildren will be the deciding factor in how you handle your step-parenting role.
It is an entirely different situation dealing with teenagers opposed to dealing with grade school or preschool children. In general, most parents have difficulty raising teenage children, so don't feel bad if you're not accepted. The teenagers may not accept you, but this does not mean you have no power or control now that you are in their life. After all, parents aren't the only authority figures in the lives of children -they also have teachers and others in the community as well. You should be aware that your role as their step parent is a combination of one of friendship and authority. Step children in their teenage years are more than likely never accept you as their parent, so don't worry about it and just give it your best shot.
It's important that you communicate with your partner about your ideas and policies when it comes to raising children. You want to do this because life is not predictable and differences of opinion will arise from time to time.
For instance, a simple rule is that the biological parent should always have command over decisions made regarding the step children. As the step parent, however, you need to have the ability to voice whatever opinions or thoughts you may have. Interactions with the children must always be done with both parents united together, or else there may be friction and dissension within the family.
Although it would be nice if your role in this new family could be accepted instantly, that is probably not going to happen. After enough time has passed, the step children will begin to accept you as a person in their lives and your adventure with this new family will be fulfilling. Keep in mind that after much time has passed, your acceptance in this new family will eventually come, but it will only happen without forcing it to occur.