Technically, it's "where and how to begin" but I'm so ludicrously new to this I can't tell you what anyone else does, just what I do. Yes, I'm pedantic. So shoot me.
Anyhow. Technically, we started homeschooling last year for Junior Kindergarten, when Monkey turned four. His age peers were all heading off to JK, and Monkey stayed in preschool... while functioning much higher. So we dinked along, we did really well for ourselves. We finished several books and started new ones, and it didn't occur to me to think it odd. Then we moved forward to this year. I order curricula in March, when we get tax returns in, and I plan what to do after that for social and extracurriculars.
For curricula, I essentially went around listening to everyone I could find who was homeschooling. Every single person. From Smrt Mama over at the McLearnins Academy for Smrt Learnins, through to Patchfire, and to my homeschooling mama-friends over at Contrary to Popular Parenting. I looked at what everyone was doing. I took some input from The Well-Trained Mind as well. I pulled together what looked like it covered everything, and would keep us solid in subjects for a good while. We learned quickly that some things just won't work for everyone. I was kind of surprised by that, as being a schoolteacher by trade, I'm used to THIS BOOK FOR EVERYONE. How could a good history book like Story of the World not work for us? Madness! But, it didn't, and we're still kind of wobbling all over for the subject, working from a core of story-ish books, and moving out from there.
This year, before we begin school - which will probably be on Thursday, holy crap!! - I went through our local Mooselandia area standards for primary grades, figuring I'd get a handle on what I was doing. Well, after finding the Mooselandia standards a nearly-unusable wreck (for my purposes, anyhow), I started "fixing" them. I pulled them all off the website for K-3. I sorted them by subject, labeled them by grade, and stuck them together in a lovely spreadsheet for my own use. That was kind of where my trouble began.
See, I took the standards, and I checked off which of them Monkey was able to meet. I gave myself a panic attack - first at his abilities globally, and then again at the discrepancy between his maths and science and his reading. So, quite naturally, I flipped out. This lasted about a week. Happily, it was still break-time. So it didn't "cost" us anything. Now that I have my head back on straight, I'm getting things ready for the fall. I picked a manipulative-based math program, and Monkey enjoys it. I started him a level below what I thought he could do because I know his fine motor skills aren't his top thing. Knowing this, I purchased two years of maths books last year, and another this year. He blew through Right Start A in no time, and is about a third of the way through B.
Science, I took a lot of confusing time with. We ended up going with Thames and Kosmos Little Labs for the bulk of things, as it covers most science easily, without making it unnecessarily difficult or boring. Monkey EATS UP science, though, so while I have enough labs for now... I've been watching another science book for when we're done with what we have.
Many of the "softer" sciences I find we cover just in daily living. Social Studies is handled on a walk to the park, or the pharmacy! Who are the people in your neighborhood, right? As far as History proper, I'm finding storybooks to be the way to go...
I'm fairly sure this is boring. But, honestly, I write it to say that we got what we thought would be good. And some of it was perfect. Some of it was so awful we needed to stop, and some of it was so wonderful we're going through it far faster than I thought we would. It ends up being a big guessing game. You go with your gut, then make changes as you see how things work. If you have a spectacular maths program you love, but your kid hates it? Just drop it. That's all you can really do. Trying to force it is part of why we're not putting our kids in public school, right? Just drop it, and try something new. Beg, borrow, whatever you have to do to get a free trial if need be... Trust me. You'll all be happier if you just drop what isn't working. And if something is working too well, and you're afraid you're going to finish it all in a week? Great! Go at whatever speed you want to, and replace as you can. You bought (likely) a year's worth of stuff, who cares if they go through it in a week? They still got the year's worth of learning out of it!
Yes. I, the panicking queen, am pretty much telling you to just roll with it. There's not much else you can do, and please, I've had my panic attack already - allow it to have been yours as well. ^_~
Honestly, that is really the hard part. Everything comes with teacher's guides anymore, so all you have to do is open the book, and it's already got the lessons written out for you! Actually presenting the material to the child is the easiest part of this whole gig. Getting the kids to sit still for it, well, let me know if you have any good ideas, 'cause I'm flat out.