First some terminology to avoid confusion:
The warp is the fixed thread on your loom. The weft is the thread you have on your needle and pass through. See
https://en.wikipedia.org/wiki/Warp_and_weftSarosh wrote on Oct 8
th, 2019 at 1:04pm:
How do you make the warp so perfect?
Training and experience
. It's all about the right tension and spacing.
Some tips:
1) There is too much tension on your weft. In the blue circle you can see how you pull your warp out of position. Use less tension on your weft, if you want your textile weft-faced (i.e. the weft showing). The weft should lie in there loosely (but snug), so that you can beat it up.
Make sure your warp is well tensioned. The warps should not be pulled out of position.
2) Your warps are quite dense. If you space them more it will be easier.
See
https://peggyosterkamp.com/peggys-weaving-tips-sett-weaving-balanced-warpfaced-w... for example. See in the density image how a little less dense warps can have quite an impact.
3) If its too hard to pull your weft through at the edge, move it further away into the middle. It's easier there. You have to tension the warps in the end either way, so it doesn't matter that much if you work right at the edge or not.
4) The more warps you have, the more difficult it will be. Start with ~10 warps or so (see the second picture) and experiment until you are satisfied and have a feeling for it. Then go larger.
5) Instead of a comb it is also possible to use a weaving sword. In the "beating" photo I pushed the threads up with the needle, as shown by the red arrow. That might be easier if your comb is not stable enough. In this part I intentionally had the warps very densely packed.
6) work evenly, smoothly and slowly. If you yank, you can't control your tension.
7) it takes a couple rows (4-5 rows) to look nice. Make ~5-10 rows and arrange them. If you don't like it, start over.
I hope that helps you.
On a side note: Both Lahun slings (the Manchester one and the one in the Petrie museum) are not a plain weaves but twined. But I guess that doesn't bother you at the moment