You'd probably want to study your inspiration material, what sort of style do you want? Hand painted style is quite general and there's many types of different hand painted art styles (warcraft, zelda BoTW, borderlands, team fortress 2 ; all have varying styles). Make a mood board with references and inspiration to get an…
Great start! I'd like to echo @mhofever that it would be helpful, both for yourself and for the people giving feedback, if you posted your references and inspirational material. I also think it would be helpful to make a benchmark by creating a much smaller scene, maybe a fork in the road or something where you can show…