In the first video Carrie, the Watercolor Misfit, gives a basic overview of the approach of a simple graduated wash:
I really like Carrie's approach to tutorials, it's very friendly and inviting. Her style is unique, to me at least, and so I find I just like watching her videos even if I already know the technique.
The second video, by Danica Sills, takes it a bit farther and goes into the topic of variegated washes as well.
I think both videos, combined, give the best overall lesson on the topic.
My quick go at the combined approach this morning resulted in:
One lesson the from that... Pick a better colour blend!
On a side note, I picked up a Darice Multipurpose Heat Tool from Amazon the other day and used it to dry the sheet. Works really well! That will certainly help with my lack of patience around drying times...