Start with a pair of leggings that fits your child. I am pretty cheap and use old newspaper for my patterns ;). Lay your leggings (in half) on the material you will be making your pattern out of. You going to want to add your seam allowances on the side. I used 1/4″ seam allowance. Then you are going to want to add onto the top and bottom to allow for hemming and for the elastic band. To determine how much you will need measure your elastic (I used 3/4″ elastic) and add 1/4″ (or however much you want your allowance to be. For the bottom, decide how much you want for your hem. If you are going to simply turn it up (since knits don’t fray) just add however much you want turned up. If you want to enclose it (ex: 1/4″, then another 1/4″) add those together and add that much to the bottom of your pattern.
Now lay your pattern piece on the fold of the fabric you are going to make the leggings out of. Cut around the outside of the pattern, leaving the fold intact. Do this twice.
Unfold your pieces and they should look like this!
Now to make the lace insert, cut a piece of newspaper that is the same width as the bottom of your legging. Lay it on your legging piece. Mark the middle of the newspaper. Then from the middle mark on each side how wide you want it to be. Now decide how tall you want the lace and make a mark directly up from the middle mark you made earlier. Now that you have your marks, lay a ruler diagonal from the bottom mark to the top and draw a line. Do this for the other side to form a triangle.
Now hem the bottom.
Lay your triangle pattern piece on the wrong side of your leg and trace around it with a disappearing fabric marker. Cut the inside of the triangle out.
Lay your triangle pattern on your lace and cut the lace out making sure you cut the lace atleast 1/4″ bigger than the pattern. I just eyeballed it. No need to measure and get it perfect, you will be trimming the lace anyway.
Lay the right side of the lace on the wrong side your legging fabric. Pin in place making sure the pins are on the right side of the legging. Sew around the triangle (on the actual legging fabric), very close to the lace. Trim your lace.
Next lay your two pieces of leggings right sides together and sew from the top corner to the point as shown above.
Once the sides are sewn, fold the leggings the opposite of how they are folded, bringing the points together. Pin and sew up the legs.
You can attach the elastic two different ways. The first way is the way shown in the pictures. Cut your elastic about 1-2″ shorter than the waistband on the leggings. Now pin it on. I usually do this by pinning in quarters, then adding pins where needed to space the elastic evenly.
Next you are going to want to serge (without blade) or zig zag stitch the elastic to the TOP of the legging. You will have to gently pull the elastic as you are sewing to get it to match up to the legging fabric (since the elastic is shorter than the fabric). Next you are going to fold down the elastic and fabric and sew on the very bottom of the elastic/fabric. Again gently pulling. I like this method because it gathers more evenly and keeps the elastic from rolling in the casing.
The second method is to fold down the top 1″ (if using 3/4″ elastic) and sew a casing. Make sure you leave a inch or so open to insert the elastic. Next insert the elastic. Sew the elastic ends together and sew the opening shut.
Now you are all done! Enjoy your beautiful creation!