This is just a short post sharing a random tip I've picked up along the way. I've seen a few weavers in person using this technique and read about it online. So, in case you hadn't heard of it, or just need a bit more endorsement before giving it a try, here you go.
When starting a new weaving you should do the first two or three passes with some sort of card stock. My current ones are actually thin plastic, kind of like Tupperware. The ones pictured are scrap bits of mat board used for framing pictures. They finally wore out which is why I now use the plastic. For one really wide project I used the cardboard backing from some packaging. Anything stiff but easily cut will do.
You cut them to be about an inch longer than your bands width and about 1/4 to 1/2 inch wide. They can be way longer than the width of your band but you might find it annoying. I have a couple different sizes for different bands.
The use of these cards is to allow you to set the beginning of your weaving without wasting any material. It's pretty much impossible to pull the weaving in to it's proper width straight off. Before I started using these cards it took me about an inch or so to pull in the warps. With these cards you put them in, then you can push the warps together and they'll stay there. Then when you start weaving the width is very quickly set.
It gives a much nicer, more professional look. This is fairly important if you want to make belts or sashes that have fringe left on. There's no option for cutting off the mis-woven beginning so it needs to look good straight off.
Here's a couple pictures of what I'm talking about: