The sequence I normally use is:
1. Make the rope needed for all the shrouds on one mast, and prepare the necessary number of lines in about the right lengths.
2. Seize one deadeye in one end of one shroud pair (i.e., one piece of line that's long enough to make two shrouds).
3. Pass the other end of the shroud around the masthead and seize it, with the deadeye hanging slightly above the right height.
4. Rig the lanyard between the upper and lower deadeyes for the first shroud. Pulling the lanyard taut brings the upper deadeye to the correct height - i.e., the correct distance from the lower deadeye.
5. Seize another deadeye into the other end of the shroud, at a point where that deadeye hangs slightly above its correct height (i.e., level with the other upper deadeye).
6. Rig the lanyard for the second shroud, using it to bring the two deadeyes the correct distance apart.
7. Repeat for all the other shroud pairs.
8. Rig the futtock staves and sheer poles (if any).
9. Rig the ratlines.
On my little Hancock model I added one other step. The upper end of each shroud is supposed to be wormed and served for a distance of about eight feet on either side of the masthead. (The foremost shroud is wormed and served all the way down.) In photos of old ships the bights of the shrouds and stays where they pass around the mastheads have a distinctive appearance, caused by the serving and the tar that was applied afterward. I represented that on the Hancock model by coating the upper ends of the shrouds with a mixture of artist's "modeling paste," white glue, and acrylic paint. That had the effect of fattening the line slightly and smoothing the surface of it. When the concoction dried it was brittle and chipped off easily, but that didn't matter much; it was fairly easy to avoid scraping or bruising it till the model was done. I don't know that I'd recommend that trick on a large-scale model, but I was pretty happy with it on 1/128 scale.
That's a pretty old-fashioned way to set up shrouds. I've tried various tricks to get around some of the awkward parts (e.g., setting up deadeyes and lanyards in advance), but in my experience none of them really helped much. My observation has been that the more experience a modeler gets, the less he/she relies on jigs and shortcuts - not because there's anything "improper" or "lazy" about them, but because they usually don't work as well, or as quickly, as the old-fashioned methods. Getting the deadeyes the right distance apart, without introducing either too little or too much tension on one or more of the shrouds, does take a little practice - and, every so often, the willingness to scrap a line or two and start over with it. But once my fingers get into gear on such a project, I suspect I can work faster than I could with any sort of jig or other gadget.
I should say that I do know of a few outstanding modelers (Donald McNarry and John Wilson come to mind immediately) who get outstanding results by pre-assembling shrouds and ratlines (and various other block and tackle assemblies) separately from their models. Those modelers work on very small scales, and use wire instead of thread for their rigging. (Mr. Wilson gets beautiful results by making shrouds and ratlines on a jig and soldering the joints with liquid solder and a torch. And Mr. McNarry's models, none of them bigger than 1/192 scale, are exquisite works of art in every sense.) The whole process of rigging a ship model changes a great deal when you use wire instead of thread. I've never had much inclination to go that route - except in the cases of extremely fine lines, like ratlines.
Several days ago I asked if anybody on the Forum had built, or knew of anybody who had built, either the Heller Victory or the Heller Soleil Royal "out of the box" - i.e., without fastening the yards to the masts, without replacing any of the plastic blocks, deadeyes, stanchions, eyebolts, etc. with aftermarket parts, and without augmenting the instructions with books or other references. So far I haven't seen any responses. For a while Heller was selling its Victory with a photo of a completed model on the box top; it looked pretty awful (even my wife thought so, when she saw one of those boxes in a hobby shop), but I didn't look closely enough to see whether the builder had in fact used the blocks and deadeyes that came with the kit. At any rate, the model in that picture was the only one I've ever seen that came anywhere near demonstrating that the kit could be built "out of the box." Apart from the question of why anybody would try to do that, I continue to question whether it can be done.