Of course making bracelets for dolls is about the easiest thing possible and I bet you already know how it's done without a fancy explanation. You might still save on some time and material by doing it my way so let me share a short tutorial.

What you need is beads (plastic, seed beads (in Europe we mostly call them rocailles), wood or whatever) and elastic thread. Also some scissors and glue, preferably PVA glue or fabric glue.

Start by soaking the end of the elastic thread with glue and let it dry thouroughly.
When it is dry make an angular cut so the hard end of the thread becomes pointed. That makes it easier to bead the breacelet.
Now, instead of making only one bracelet make a whole bunch at once! Depending on their size 10-16 beads is a good size for a bracelet. My beads are mostly 2.6mm and to make a bracelet for Pullip 14 beads is usually perfect. So put them all onto the elastic thread and don't cut off the end.

Once you have all beads that you want in place carefully make a double knot to finish the first one.
Cut off the thread about 5mm behind the knot and finish the next bracelet and the next and the next...
That saves a lot of elastic thread as you can reuse half of the thread you need to actually grip and tie the knot for the next bracelet! It also saves you time as you don't have to fumble about a good pointed thread tip for every separate bracelet.

To finish off the bracelets pull them over your finger and secure the knot with some glue. Be aware that this doesn't last forever but it's quite sturdy. I used to use super glue for this but was advised that this hardens the knot and over time lets it break. PVA glue, however, was even recommended as fray-stopper by a professional dollmaker, and fabric glue should be fine too.

Put the heap of bracelets aside until dried, then cut off the loose threads and enjoy your growing stash of jewelery! Huzzah!

I know some people use elastic invisible thread / elastic nylon for this instead. Looks good too but I never saw it for sale myself so I couldn't try it yet.