craftgrrl | hemp jewelry question...

sorry for the text-only post, but i have a question for you crafty ladies about making hemp jewelry. i searched the memories and couldn't find anything dealing with my specific question...

i decided i wanted to teach myself how to make hemp jewelry. i've got the basic knots down, but my problem is where to place the beads. i've done ok with the one or two i've made so far, putting just one bead in the middle. do you guys have any quick tips on how to get the beads where you want them? i've been frustrated because i've had to undo the two i've made as it is!! it just seems like there's a lot of estimating in this craft...

thanks!!