How to draw removable guides on fabric
When stitching my embroidery sample, I used a pen to draw grids so I knew where to put my stitches. And when helping my friends out with their embroideries, they used the same pen to draw out their designs. This won't work if you already have a design that you need to trace exactly, but if you're drawing it freehand, or you're confident with what you're doing, this would totally work.
I think it'd be great for pattern drafting for clothes too, because it's a lot thinner and thus more precise than using fabric chalk or pencil. Plus, it wouldn't rub off like the chalk or pencil would with friction.
This is what I use: a 0.7 Frixion ball pen from Pilot
Pilot has a range of Frixion pens, but this is the only one that I've found that can easily leave marks on fabric. I literally went into the stationery store and tried to draw on my tote bag, and my pants because those were the general materials I wanted to work with.
Something to note with this pen is that it doesn't work on dark fabrics. But for lighter coloured fabrics, they're amazing. Remember to bring a swatch to the stationery store to try it before buying!
How this works: Frixion pens are marketed as erasable with friction, but it's not the friction that removes the ink, it's the heat. If you write on paper, you'd get a cleaner ink removal by placing the paper on a heated surface (like a recently boiled kettle) than using the rubber top it provides to rub with. So, basically, just draw on the fabric and to remove it, iron the piece! The finished embroidered piece always looks better after it has been ironed anyway.