I must have taught hundreds of people to spin, and it's best described as Trishbo said when she learned; it's a lightbulb moment. It suddenly all just comes together
and you've got it
I'm a pain; I honestly believe that machine made was made in emulation of the best of hand made. The ladies who taught me to spin were elderly, and their spinning was fine and even and sound. An awful lot of folks who spin now, spin 'designer' yarn.......all lumps and bumps and thick and thin, underspun, overspun........learn to make it right first and then you can play around with it all you like.
I think for the string you want, the fibres would be best worsted spun. That is with all of them lying in the one direction, not an open, airy, knitting wool type yarn, but a non stretch weaving type yarn. Smooth and even.
The bast fibres are best spun damp so keep a wee bowl of water beside you and use it to keep your fingers moist; or, if you can make a roving of the fibres first, just spray them with water from a plant mister bottle. (a cleaned out squirty cleanser bottle works fine too)
Oh no pressure; it's just among ourselves and we're interested
Flax is carded on a comb, and I use a metal dog comb to clean my nettle fibres. Just hold tight on the end of a bundle of the stuff and comb until the other end is open and clean, then turn the bundle round and do the other end.
I want the fibres all running parallel, and I find it easier that way. If I use carders I get a soft woolly like bundle.
cheers,
Toddy