The pros and cons of wearing tops with bows has been debated over at PatternReview, but whether or not you think they're appropriate after a "certain age," bows are undeniably a part of today's fashion scene. And, of course, bows are always in fashion for little girls. Being able to tie a symmetrical bow that sits level rather than flopping limply to one side or the other is crucial to pulling the look together.
Keep in mind that there's nothing so special about tying the perfect bow. You most likely tie bows just like this when you tie your shoes. So I've documented a lot of steps here, but remember, you're really just tying a bow.
Cross one sash end over the other. I'm left handed, so it works well for me to cross the right sash end (B) over the left sash end (A). If you're right-handed, it may work better for you to cross the left over the right; just remember to reverse all the steps.*
Now the right sash end, B is on the left, and the left sash end, A is on the right. From now on, I'll just refer to B and A. Fold B up behind A and over to form a half knot.
Pull your half knot snug, but not uncomfortably so.
With A, form a loop up close to the half knot. This is the most important part of tying a perfect bow: the loop must always be formed with the tail that comes from the bottom of the half knot. B must be kept on top. This is the only thing that differentiates a perfect bow from a bow that twists to one side.
Bring B over the top and in front of Loop A.
Pass B behind the Loop A. Form a loop from B and push it back through the space you created when bringing B over and then under Loop A.
Pull Loop B all the way through.
Pull your knot snug. Adjust your bow by alternately pulling on the loops and tails until you have a nice proportion of loop to tail.
Your finished bow:
Notes: You can apply this procedure to tying a nice knot, for example, on the belt of a coat. Just remember to keep B on top.
Your finished knot:
And here's what happens if you forget to keep B on top. Ugh!
This type of bow is better suited to a two-sided sash or ribbon, but it is possible to tie a nice bow with single-sided as well. Just remember to keep the right side of the sash/ribbon properly oriented at all times. You will have to twist the ribbon as you're pushing Loop B back through on itself; the trick here is to make sure that the twist ends up in the knot as opposed to on either side of it. Here's a picture of a bow tied with single-sided ribbon, just to prove that it's possible.
*This is a small but satisfying payback for the countless times I've read and tried to reverse directions written from a right-handed perspective.