It takes planning to be a good parent. Planning is also important in other ways. For example, if your kids are tired, hungry, or sick, don't take them shopping, out to eat, etc., unless you want to invite problems. If you must take them out, don't blame them for being kids; it's your fault for poor planning. Take snacks, expect the worst, and hope for the best. That's all I'm going to say about that.
We all parent on the fly, but if you can learn to just do develop this one little/big skill, you will be far ahead in preventing discipline problems: Alert your child to upcoming transitions. I cannot emphasize this enough; you will have a lot less conflicts getting your kids to leave the house, or a playdate, or just switch from one activity to another if you give them a heads-up. Let them know that a transition is going to occur; don't just say, "It's time to go," and expect them to drop everything. If you want to be really proactive, ask your child at the start to tell you what the plan is for stopping. Tell them, use a visual timer, and ask them to tell you what the plan is. (Get their eye contact, first.) Making transitions is much easier if you provide the structure that planning provides. Planning = security.
The first thing Super Nanny does when she works with a family is set up a routine/structure for their family. That's because structure is very important to children (and most adults). The relative predictability of a routine provides security. To me, the most important thing you need to structure if you want happy, healthy kids and parents is bedtime. SuperNanny has plenty of episodes that show how to get your kids to bed, but she never talks about structuring the bedtime routine itself. It truly breaks my heart when I hear people say, "This is how they always 'go to bed," they just run around until they wear themselves out and then crash wherever. When they're sleeping, we put them in bed. Later, they wake up and get into our beds." This is crazy, people! If your kids do not have a bedtime routine, you are cheating them (and yourselves) out of an opportunity for some wonderful, intimate quiet time together. I guarantee you that if you work on the attention piece as I've suggested, instituting a bedtime routine will be much easier to implement.
I'd be happy to talk more about how to set up a bedtime routine, but in general, a basic routine at our house included: Snack. TV show. Bathe. Teeth. Story. Prayers. Kisses. Good night. They learned the routine and took comfort in it. In fact, their routines today (as teenagers) are pretty close to the same as they were when they were kids. Aside from Kyle's first year (when we Feberized him), we have never had a single problem getting our kids to bed and having them stay there. They did cuddle in bed with us, but that was part of a morning routine.
If you don't have a routine now, it will be harder to establish one, but your kids will eventually love it; trust me. If this is an emergency, and you are desperate to get this started now, email me. Otherwise, watch for a post on this soon.