One trick I use in a canoe, if I don't have to paddle a long distance, is to sit on a large picnic cooler in the middle of the canoe. It gets me a lot higher up in the air than I would be if I were sitting down in the stern. I started doing this to distribute my weight evenly in the canoe so that waves won't slap the bow when I'm solo, but then I found out that it makes flycasting easier too. Also, it's easier when I want to stand up and cast because I'm already more or less in the middle of the boat. (My old fiberglass clunker was better for standing than my new and improved kevlar canoe.)
I don't think that this would work in a touring canoe with a narrow beam, because the cooler might not fit, but in an ordinary fishing canoe, with a more or less flat bottom, for when you're puttering around ponds, it works great.