Lastolite has a section of free video tutorials. Reflectors, umbrellas, background lighting, Ezybox hotshoe (lightbox for small flashes/speedlights) etc.
It’s Lastolite products, but you’ll get the idea 
even if you don’t use their product. Mark Cleghorn does the free demos. I like his book on portrait techniques. He understands lighting very well and he has a nice touch with working with people.
There’s two nice ones in there that describe and show the different kinds of umbrellas and reflectors.
Have a look at the demo on the Ezybox hotshoe portable softbox for flashes. A very portable solution for using speedlights on location. It can be mounted on a stand or a pole. It folds up very small compared to most softboxes.
Although the videos are designed to show you how to use Lastolite products, they also push your creative thinking.
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