I agree with the others in doing color studies and smaller thumbnails. I use to not do any preplanning because I'd be so excited to get to the painting. Since starting to plan ahead of time though, I've found my paintings to really improve and come out closer to what I had initially envisioned. I feel like you could play with color temperature more here. You could push the cool, less life-like colors in the background and then push some more warm, rosy colors to the figure, to help show how spring time brings about blooms, life, etc. Your figure is looking good and I like the gesture of her pose! Similar to what Luigi and Yiming said, taking color notes from the background and adding them onto the figure will also be a good way to tie the background and figure together. Also the contrast of those cooler notes on the warmer skin will help those colors pop more.

An updated, very small colourstudy, that will bring it closer to what I want.

Really cool painting @Mattias Wirf! When I get stuck on a painting, I kind of have a checklist of concepts I like to roll through to make sure each aspect of my piece is working. For this one, I brought it back to the value stage and focused a bit more on values, light, and a tiny bit on composition. So, the lighting logic on your figure is off, BUT I do like how it basically turns the figure into a very clear bright shape to help her stand out in the composition. I'd say if you want to keep the light like this, it might be ok in this scenario. I just cleaned up your shadows a bit so that the shadow value matches the upper part of the leg that's completely in shadow. Additionally, I added a cast shadow to bring a bit more light logic to the piece. To contrast with the idea of 'Spring', I think it might be a cool idea to add variety to the background through the trees. I've chosen to use trees without leaves on them, which gives them a more threatening shape that contrasts with the main focus of your piece. You don't necessarily have to go in this direction, but it is a good idea to consider how you can use background elements to add variety to your painting, and give greater emphasis to your focal areas. I also think that Yiming's comment on color is valid as well. The areas like the grass and dirt in the foreground seem a bit too warm, especially when the colors should be influenced by the ambient cool light that we can see in the background. Hope you found this helpful! Let me know if there is anything that I can clear up for you.

This is an unusual and interesting pose. I think what you could do next is to add indirect light reflections. You see the human colour is a bit "disconnected" with the whole frame, so it might be good to introduce some blue/green-ish reflections on her skin so the viewer can see it's united. the leg seems to have that idea already, it might be the brightness is too high as a reflection so it didn't quite unite the image that well.