I wrote this up for a friend who's learning to sew and thought it might be of use to someone on this comm, as well, since I don't see any sort of cutsew-from-scratch tutorial. This is a really basic, fast project with raglan sleeves (the easiest for beginners, I think) so it should work well for a functional beginner or lazy seamstress (I'm the latter.) I made this for a friend with a 37" bust, so the measurements given yield a US size ~M with an unstretched bust measurement of roughly 35/36". Knit is forgiving size-wise, though, and this can be fairly easily altered down for the petite among us. All seam allowances are about a half inch. (I'm not huge on precision when it comes to knit :) On that note - keep in mind that knit is stretchy, which can make it a bit fussier to sew if you're used to woven cotton but it also means you can fudge a little bit to get stuff to line up. Any time you need things to match up, pin the seams together and ease the pieces to line up as you feed the fabric through the machine.
The (unhemmed :) final product looks like this (please to be ignoring the clutter; am a messy thinker) -
It can be finished with a normal hem, or a ruffle (like Baby's Marie Antoinette cutsew), or turned into a cutsew dress with the addition of a skirt and side zipper. This top was done cutsew style with a serger, but a serger or serger attachment isn't necessary. On a regular machine, I prefer to use a narrow zigzag and gently pull the fabric through the machine. You may wish to experiment on a scrap; the point is just to ensure the thread won't break if the knit stretches. After sewing, clip the seam allowance down and run a zigzag stitch over the edge to keep them neat.
* Stretch knit, roughly 2/3 yards if buying off the bolt.
* Lace is optional, takes about 1.5 yards to go around the neck hole. To trim cuffs, add another ~1.5 yds.
The top diagram is for a skirt. For the cutsew you'll just need the bottom two pieces outlined in red. These drawings aren't to scale, but are easy to replicate on paper. Start with a rectangle 22 x 9" for the sleeve and 18.5 x ~19" for the front and back. Trace and cut out the pattern on the fold.
If you wish to scale the pattern down, reduce the width of the top and sleeve. The width of the front and back should be roughly 1/2 your bust measurement. Reduce the width from the center fold, as this will also reduce the width of the neckhole (if you shorten from the side the sleeve won't fit and the neckhole will be too big). The sleeves can be shorted by a few inches in width and 1 - 1.5" in length so as not to appear too large (all other measurements stay the same, no need to reduce proportionally).
Now that you have your pattern pieces cut out, they should look something like this -
Cut two cuffs for the sleeves by cutting a width of fabric the length of your arm measurement +1" (the cuff on the example is 14") x 3". The 3" measurement yeilds a finished cuff width of about an inch. You can cut it to 2.5" or 2" for a narrower band. Press the cuff in half lengthwise, right side out so it now measures 14 x 1.5".
Gather the top and bottom of each sleeve, gathering the bottom to fit the width of the cuff. Sew the cuff to the sleeve. It should look like this when you're done:
Sew both of the sleeves to the top on one side, like so -
Cut another rectangle 20.5 x 3" (again, this yields a ~1" band. Reduce this measurement as desired). Press in half length wise and mark off 5" on both ends. If you reduced the size of the top, you'll want to reduce these measurements as well. The 5" measurement will be the distance over your shoulders. You don't have to have a precisely measured piece for this step as you can trim off excess fabric, but make sure the sleeves are gathered to the same size on both sides.
If you want to add lace, gather and baste it to the neck binding now. The bottom edge of the lace should face the fold in the binding.
Pin the binding to the top, matching the chalk mark to the seam where the sleve joins the top. (I have the seam marked with a pin).
The finished back should look like this -
Cut another strip to make a neck binding for the front. Add lace as necessary and sew it on, giving you two final pieces like so -
Join the front and back together at the sleeves.
Fold the top inside out and line up the cuff edges. Align and pin the seams at the top of the cuff and under the arm so they don't shift out of place as you sew. Running one continuous seam, sew from the bottom of the sleeve along the side of the top to the hem. It's the white line in this picture.
Hem or finish as desired, add a screen print or applique (someday I'll make a black and white one like this with a treble clef and notes appliqued on :), and you're done! The neck binding benefits from being top stitched down, but in my experiences this takes a walking foot (otherwise the knit has a tendency to stretch) so if you don't have one just press the seam so the neck binding lays nice and flat.