We hope to do that (learn the FP+ and understand the ins and outs) we got a book on WDW (with kids) and I'm making headway through it (for a second time - first time I focused on the dining portion, this time I am focusing on the parks, the rides, etc...)
There is a great thread in this forum all about FP+. Read through that, it won't take all that long, and you'll learn a TON about how it all works. Then if you have questions, ask away here.
The biggest thing I try to tell WDW newbies is to NOT stress out to the point it's no longer fun. WDW is supposed to be magical, don't plan the magic out of it. For some people, planning is part of the magic, and that's fantastic. I like wdw&sonny's post above. Come up with at least a loose plan. If you use it, fantastic, but if you don't or if it falls apart, then don't stress about it.
I'll tell you exactly how DW and I plan, we just did it again a few weeks ago for our upcoming July trip. We don't eat in the restaurants, we pack our own food, so keep in mind we don't have to worry about dining reservations. We grab an 8x11 sheet of paper and write down all the days of our trip. Monday, Tuesday, etc... We then start with MK, because for us it's tradition to start every trip there. From there, we simply do a variety of parks. We don't go exactly A,B,C,D,A,B,C,D, but we rotate relatively evenly...with a slight bias toward MK. No rhyme or reason to our selections...we don't look at crowd calendars, EMH, etc...just pick parks on a whim. Since we're not the types to stay in the park from open to close, we'll put AM or PM next to the park. So for example, on this trip, Friday is our first park day. I have to work that day (my job is kind enough to let me work remote), so we can't even go to the park until late afternoon. So the paper says "Friday - MK PM" Then Saturday is "DQ (Disney Quest) morning, HS mid-afternoon". Sunday says "Epcot AM", Monday "AK PM", etc... We then grab the appropriate FP+ when the window opens. No particular strategy to that either, just grab rides we can get and what the kids would want to get on. We fill the times between FP+ getting on other rides that don't need them.
The times that don't have something written down on our sheet, such as Sunday PM in our above plan (since we're in Epcot for the AM), is what we call "freestyle" time. That literally means we decide on the spot what to do. That leaves so much flexibility, we love it. So on Sunday, when we're eating lunch in Epcot, we'll ask the kids "What do you want to do this afternoon?" If they want to stay in Epcot, great. Want to head to MK? Let's go (check
MDE before we go to make sure there's something they'd ride that doesn't have a long line and/or we can get a FP+ for it). Sometimes they're tired and we just want to go back to the condo. Great.
That "planning" we do on the 8x11 sheet of paper is done in less time than it takes us to drink a cup of coffee at Dunkin' Donuts, literally. It's all of 40 minutes or so...and that's for a 17 day trip. Certainly, we have a big advantage because we're WDW veterans, but you get my drift. We have a very loose plan, so we have some concept of where we're going on a given day, but more than half of the time is freestyle, and even sometimes we'll change our FP+ for the next day because the kids want to.
Plan or not, I definitely suggest doing reading here, you'll learn a ton.