Several years ago I worked with our local newspaper and gave them my recipe for meringue. It's the one I use for lemon meringue pie. It uses an extra egg white so that I can get mile high meringue on top. I didn't put in baking instructions since this was supposed to be a generic meringue recipe and shold be baked according to your recipe. Meringue instructions
You can't make a good one without using cornstarch. It won't set up properly. I like to put just a little meringue inside the lemon filling to lighten it up just a bit.
I put the meringue over hot filling so it bakes properly.
If you make it on a humid or rainy day, your pie will not set up properly. The meringue will get beads of moisture. I have not tried this, but some people told me that they sprinkle a little bread crumbs on top of the lemon mixture right before they put on the meringue. It's supposed to soak up the extra moisture. I might try using ground almonds instead.
Lemon meringue pie can be difficult to make, even for an experienced baker. But it's fabulous even when not perfect.