Environment art starts with two important steps: references and thumbnails. References are the first step, and thumbnails are what ideas will actually look like. Artists in different fields use references to make their art more believable rather than recalling from their memory how objects look like.
Thumbnails are quick and lose first visualizations of ideas based on references. First drafts don't have details, but the overall design and feel of how the environment could look like.
Relying solely on memory can lead to mistakes and misinformation. Unfortunately, the brain limits visual memories so it can function economically without overloading.
For example, people often have difficulty drawing bicycles from memory.
Using references is not for directly copying them, but to study and to understand how things act and interact with other objects. For example, how folds act on a dress when it's windy or the structure of an airplane.
Reference boards are meant to gather the references into one collection. Images, fonts, colors, anything that is useable as a reference, and what the final art piece will be built upon. The collection of resource material defines the guidelines and the rules you are going to follow during the process.
Below is an example reference board for a knight.
Reference boards are also a way to communicate with others as images tell more than just words, especially if you are working in the entertainment industry like video game development. Communicating the overall style of the game is essential information for the artists to make the game look cohesive and united.
Thumbnails are small and quick sketches that are meant to explore design ideas and eliminate bad ones. They are quick, sometimes just bare scribbles or more structured shapes. Achieving the best style to make thumbnails requires practice and exploration. Simple scribbles can be enough for you to make out what design elements work, or maybe you like to take your thumbnails a bit further.
Thumbnails are just rough sketches and not final concepts while still including most of the final design elements. Some artists spend more time with the thumbnails, but often the time is limited to one to three minutes per thumbnail. At that time thumbnail has all the important elements while remaining simple enough.
When making environment art concepts, thumbnails are an essential part of the process. They are more focused on the composition rather than details, as thumbnails are quite zoomed out and have only a few black-and-white values and for a beginner artist only one brush. Making one thumbnail takes only one to two minutes and making a set takes around 30 to 40 minutes.
Limiting the use of values and brushes will help the mind stay open to keep ideas flowing to the canvas. Some of the thumbnails can look awful, and that's OK. Now the idea has been tested and can be stated that it didn't work so moving to the next one.
Term value in art means how light or dark something is on a scale of white to black. As we see objects in the real world and understand them due to the lightness and darkness, making values an important part of the art fundamentals. Artists render their work using values to make their drawings have a three-dimensional illusion, depth, color contrast, and life-like appearance.