The goal, of course, is to mimic the body's normal response as well as you're able to: a gentle rise and peak instead of a sharp spike that must then come back down.
I had done quite a lot of reading and self-study before I started insulin, so I pre-bolused right from the beginning. I've always found that it makes a dramatic difference—not always perfect, but light years better than waiting. The ideal scenario is for the insulin to begin working just as the food hits the blood stream. To do that you need to know how long the insulin takes to begin working, and that's different for each type of insulin for each person. For me, for instance, Apidra starts to kick in at about 15 minutes and R at about 40. The only way to know what those numbers are for you is to do some controlled testing and watch your meter. Armed with that knowledge, you can prebolus with fair accuracy most of the time.
As the the question of "which foods", that's also a very individual thing, as you've already observed with your daughter. The only real help for this is time. As you gain experience, you will get steadily better at gauging the insulin (and timing) that give the best results. It would be lovely if there were a simple shortcut to that learning curve, but there really isn't. The good news is that you have the time: "Diabetes is a marathon, not a sprint." It's not going anywhere, and neither are you.
Further on that question, there are foods that I avoid, not so much because of timing and spikes, but simply because I try to minimize the amount of carbohydrate in my diet. So I just steer clear of white things and things full of sugar, really just to minimize the amount of carb I eat and the amount of insulin required to deal with it. (Of course, there is the occasional "vacation" or treat, but they are the exception, not the rule.)