Hello!
First off, great job for a first render. Much better than anything I made when I started out.
The Lighting:
I agree the sky dome is too bright. It's making the window areas look washed out. There are lots of ways to go about fixing that but I would recommend looking into HDRIs which are an easy way to manage exterior lighting in a scene and they can also provide a background so there is something to see out the window (trees, cityscape, neighborhood, etc.). The imagery can also be a reference point to adjust your intensity/exposure.
Also, don't rely on the exterior lighting to light the interior. Get the exterior looking natural and then supplement the interior with additional lighting. You can adjust emissives, spotlights, etc. to emulate sunlight if you're looking for that kind of effect.
Posing:
Without the context of the scene I can only speculate, so the faces seem fine. The body poses however, look a bit rigid. This is primarily in the arms and hands. Even something as simple as adding slight bending to the finger joints can go a long way to make it look more natural - the average person isn't going to sit around with all their fingers fully extended. It also appears the woman is speaking here yet the man has his arm out - maybe this could be reversed and the woman is gesticulating while she speaks. She looks a bit angry, so it again looks a bit unnatural for her to just have her hands resting on her legs.
This and
this are pose utilities I use regularly to help with hand posing, even as just a starting point. Very HANDy
Clothing:
You can see the man's skin through his shirt by his left armpit. Poke-through like that drives me crazy so it was the first thing my eyes were drawn to. Again this is something which can be tackled multiple ways - an easy/quick method if you don't want to fix in post is adding a push modifier to the clothing object (Edit > Object > Geometry > Add Push Modifier). This adds a slider to the parameters of the clothing that you can adjust to increase or decrease the thickness. Drop the slider down way low and work upwards until there's no more poke-through.
I would also familiarize yourself with the smoothing modifier/iterations for clothing. Some assets will load in with this and some will not but can be added manually like the push modifier. It can help create a more natural look as well.
Aesthetics:
The environment overall is a little bland. I think being able to see stuff out the window as mentioned above would help but I would also add something behind the woman's right shoulder - maybe like a console table with some decorative items on it, floor plant, painting/picture on the wall. Fill that empty space so it looks lived in.
This last thing could be just me but I would change either the color of the man's pants or the chairs they are sitting on. The white on white is jarring, especially with how marshmallowy white his pants are.
