[edited to change cast on amount to 16]
I added my generic top-down socks pattern to Ravelry and then realized that half of my generic socks are actually toe-up socks. One reason is that I often make socks with leftover scraps, and starting from the toe up allows me to use up the yarn without running out before it's finished. Knitting cuff-down socks with a limited amount of yarn might leave me with not enough to finish the entire foot, but knitting toe-up socks lets me stop when the yarn runs out. So anyway, I thought maybe I needed an official pattern for toe-up socks too. Here you go. This is more of just general instructions than a detailed pattern. I also don't have pictures take all along the way like I did with my previous pattern, but it's pretty straightforward. Let me know if anything is unclear!
This is how I make toe-up socks. I prefer DPNs to magic loop, but you can probably easily convert this pattern to magic loop. (Also, skip to the bottom for some notes on how I do stripes on my own socks.)
Size 1 DPNs
Fingering weight yarn
Lots of stitch markers (for marking beg of round and for short row heel)
Using Judy's Magic Cast-On, CO 16 st on 2 needles. [As a note, I start with 2 needles for casting on and then on the next round switch to 3 needles. I leave the first half the stitches on the first needle and the split the remainder between needles 2 and 3 (a quarter of the total stitches on each needle 2 and 3). This makes it easier for me to remember where the beginning of my round is. The needle with the most stitches is always my first needle, and I can keep track of things better. That's just my preference.]
Inc 4 st every other round as follows.
Round 1: (Needle 1 - Kfb, K to last 2 st, Kfb, K1); (needle 2 - Kfb, K to end); (needle 3 - K to last 2 st, Kfb, K1)
Round 2: K all st
Repeat until you have 64 st total (32 st on needle 1, 16 st each on needles 2 and 3)
After inc to 64 stitches total, knit around in st st for desired length, about 2 in less than the total foot length.
I do a short-row heel on my toe-up socks. My favorite method is Cosmicpluto Knits' short-row heel. [edit:If you've never done a short-row heel or if you normally only wrap each stitch once in a short-row heel, you will probably want to take a look at the link. Stitches are wrapped twice in this method, and my instructions are less detailed on how to do the actual technique of wrapping and picking up wraps. This is intended more as a guide for how I personally adapt that technique in my own socks as far as numbers and using stitch markers, so if you have any confusion with my instructions, check out the link above for more detailed information and lots of pictures.]
For the heel, I use half of the total stitches (needle 1).
Row 1: On needle 1, K to last stitch, wrap and turn, PM (I like to place stitch markers after every wrapped stitch so that I know where I turned my work. This leaves me with a ton of stitch markers in my knitting while doing the heel, but it also saves a lot of confusion.)
Row 2: P to last stitch, wrap and turn, PM
Row 3: K to marker, wrap and turn, PM
Row 4: P to marker, wrap and turn, PM
Repeat rows 3 and 4 until you have 11 st wrapped on each side and 10 st unwrapped in the middle.
For picking up the wraps and re-wrapping, see the more detailed instructions in the above link for Cosmicpluto Knits' short row heel.
Row 1: K to marker, remove marker, pick up and knit wrap, wrap next stitch a second time and turn. (Again, leave the marker after the re-wrapped stitch in place on each row to remind you where you turned your work/left off picking up wraps.)
Row 2: P to marker, remove marker, pick up and knit wrap, wrap next stitch a second time and turn, keep marker in place
Row 3: K to marker, remove marker, pick up and knit both wraps, wrap next stitch a second time and turn, keep marker in place
Row 4: P to marker, remove marker, pick up and knit both wraps, wrap next stitch a second time and turn, keep marker in place
Repeat rows 3 and 4 until you have no more wrapped st and all 32 heel st are again live. Proceed to ankle/calf.
Resume knitting around all 64 st and continue in st st to desired length.
10 (or as many as desired) rounds in K1P1 ribbing
BO using Elizabeth Zimmerman Sewn Bind Off (last technique, at the bottom of the page)
Weave in loose ends with tapestry needle
I like to make toe-up socks with leftover sock yarn, as I mentioned above, and it's fun to try out different stripe patterns or using different colors for toes, heels, and cuffs. You can do lots of variations with different colors. I also like to make my socks opposites, like using one color for the toe/heel/cuff on the first sock and reversing the colors and stripe sequence for the second sock (like these).
For stripes, I usually change colors every 6 rows. That's about a half inch for each row. For my foot, I need 10 1/2 stripes before changing to the heel. I switch colors for the heel and then switch back to my previous color (half stripe) and finish that stripe and continue switching every 6 rows. This may work out differently if your foot is much larger or smaller, but you can use the toe color for a few extra rows to make things work out more evenly, if necessary, or add rows to each stripe. Or you can make thinner stripes, only 2 rows wide, which would make it easier to start the heel at whatever point you need (like these).