what software do you want to use? There are tutorials for doing stylized stuff in a variety of different software. Does this interest you perhaps? https://cubebrush.co/mb/products/1ztdpw
Stylized can mean a lot of things, perhaps you'd be better to study the game/genre you wish to emulate, then reproduce it. Making a stylized game asset is really the same as realistic ones except in maybe poly count and handpainted textures (which I'm sure there are many tutorials on how to create handpainted textures…