I love weaving with my students! Over the years, I've discovered a few things that make the project better/easier for the students. Here are two that I use with the 4th grade weaving project.
Hair picks make wonderful rakes for the yarn! It really helps to pack the yarn in tightly to get a great looking weave! I had made some at one point with cardboard, but they just weren't cutting it. I was able to get them at the dollar store for super cheap!
When students are pulling their weft string through, they tend to pull a bit too tightly & hourglass their weaving. This, of coarse, is undesirable. So, when they are ready to pull the string through...I have them take their pencil and press it down in the "loop" to prevent it from pulling inward. This seems to work really well for most students. Though you will always have those that don't follow directions!?!?!