Few are lucky to look back on grade school as a time of pure joy. Instead, it's usually remembered as a time when everyone was awkward—9 to 13 is definitely the ugly duckling phase of life. Not to mention your teachers have cruelly done away with things like naps and snack time. At this age, you, the parent, is the constant support, letting your child know she will outgrow pimples and that Tommy will stop pulling her braid just in time to ask her on a date somewhere down the line.
To help your child get ready for grade school, practice penmanship (this was huge for my brother), invent games that practice multiplication and division tables and maybe spend some time doing creative research projects about random countries around the world. Your biggest challenge is going to be making your child feel confident and prepared enough to perform in school and actually enjoy it. So often, kids who are worried about failing don't try at all, and the best thing you can do for them is to give them a head start and make learning fun. A little early success goes a very long way in terms of bolstering their confidence in what they already know and their willingness to learn new things.
Then they get to high school and the supposed four best years of their lives (pre-college, of course), and, once again, everyone sort of recalibrates and adjusts into the adult world of all work and no play, at least in terms of grueling classes, hours of homework and the eternal buzz about college preparation and admission processes. At this time, parents can and should be the rallying party, the sounding boards and, sometimes, the critics.
To help your teenager prepare for high school, start by helping her figure out how to specialize and find something she's passionate about. The worst thing you can do is force your child to do too many things and not give her an opportunity to actually figure out what she loves. That being said, don't let her sass you out of doing anything at all. That's what I mean when I said you might need to be her critic and force her to realize when it's time to take action. And of course, you'll hopefully also be there to reward her when she reaps the fruits of her efforts. Just remember: There's helpful feedback and kind prodding, and then there's nagging and overbearing, pushy parenting. You're the one who has to figure out how to stay positive so both you and your child can be happiest.