How do you make a good park in rct3

You should use most of all rides, a LOT scenery (or custom scenery) and make your own coasters. Make food drinks, and all stalls. And use almost anything is available
You should take some time to think everything out. You should place food, drink and stuff stalls all over the park. You should place gentle rides (coasters for kids, slow rides) on one side of the park and more extreme rides on the other side of the park. If you want to make a monorail or something similar you should leave a path for that. SHORT: Think out every detail before you start because there is no turning back!!