If you can get them, large rubber bands are good. When I do staved coffee mugs, I used to glue up one half, then glue the two halves together. It was a lot of trouble and didn't work as well as 4" hose clamps and the whole thing glued together at once.
For large segmented pieces, most glue up 2 segments at a time, then quarters, then half, then full.
If you go to YouTube and search for "Seggy's Dream" you'll see Malcolm Tibbetts, one of the premier segmenters, turning a vase. It shows some of his glue up process as well.
If you don't have it, pickup Malcolm's book it will explain everything you could want and more.