In every new project I see improvements. This is very good and the lighting is spot on, the only thing you could work on in this picture is a little fading and less opacity on the squirrels shadow and the position of the sun is a bit off. If you take a look how much stuff is covering the sun, the small opening to the right or below the right opening is a more suitable place for it to shine through as much as you wanted. A handmade sun makes better lighting as well if you paint it on already bright or open spaces. I made an example in an attachment below.
Also a good way to make a sun or lighting is to use Hard Light blending with a radial gradient. Or use Dodge blend mode for an intense light. In my example I used Hard Light.