For this month's Daily Paintworks Challenge, I proposed painting a single scene in 2 mediums (more for extra credit!). I posted the photo for this scene as an idea (but you can use anything you like). It took me a while to do it myself, but this is it, and I learned a LOT!
The top one is gouache. I did that one first. I cut a panel for #2 (oil - middle painting) the exact same size, and was really frustrated in painting it. I took a break after, and came back having decided to try one more time, on a slightly shorter panel that was leftover from cutting the other one (bottom painting). I experimented quite a bit with the whole thing - tried to approach each part a little (or a lot) differently. While the result probably looks very similar, I am much happier with the third one, and this is really where I learned.
For example after doing the second one I realized that the ground I put down tinted the whole thing kind of pink (ugh). So for #3 I didn't use a ground, and the colors came out cleaner. Also for #3 I blocked in the whole thing first and this really helped me get all the relationships working from the start without having to make big changes later. I have found in general blocking in is helpful with landscapes, since the relationships (especially value, but also color & temperature) are so critical and often subtle.
Anyway, I HIGHLY recommend doing this!! And if you do, please post what you painted to our challenge (you don't have to be a member). Happy painting!