Toni clothing is fairly easily to identify.

First of all, Ideal tagged their clothing - it is a small Toni tag, almost always sewed into the waist seam in the back hanging vertically.  Often the tag is missing, so here are some other tips:

Ideal used button closures, white buttons with swirls.  The P92 dresses generally have two buttons, while the P93s have three.  The smaller dolls will have two buttons.

Look at the waist seam, inside, if it is factory it will be serged.  Mommy-made clothing is almost never serged.

Toni dresses almost always have a muslin slip with cluny lace trim. There are a few exceptions (very few). A few of the pinafore dresses I have seen without this slip.  The slip always has the same lace which is a narrow lace which is an embroidery lace with small points.  The underwear uses the same lace and fabric.

When in doubt, refer to the Ideal Books by Judith Izen - there are a lot of pictures of clothing and pretty soon, the Toni clothing becomes easy to spot.

As a footnote, the Toni shoes! Ideal used two types of shoes: the leatherette centersnaps, and the vinyl side-buckles. The vinyl side-buckles have an embossed pattern on the top and will either be white or black. The most common is white. They will be marked "Ideal Doll Corp" on the bottom. These shoes were also used for Shirley, and other Ideal Dolls.

Happy Dolling!