How to make canvas paintings
How to make abstract paintings
How many times have you seen abstract paintings and heard someone say, "Ah, I can also paint like this!" Although abstract paintings look easy for some people, they can also be more challenging than classical or traditional paintings. This is because abstract art is against the rules and habits of art. As an artist, you are free to rule, express, and determine what can be regarded as art. First, prepare to paint. Then, determine whether you want to make random geometric abstract paintings (like Paul Yanko or Thornton Willis style), minimalist geometric abstract paintings with firm forms (like Piet Mondrian or Paul Klee style), or if you want to focus more on the painting process itself (like the Jackson Pollock or Mark Rothko style).
- Choose canvas. You can buy ready-made canvas of any size at the craft shop. This canvas can usually be used immediately; however, there are no rules that say you must use a canvas that has been coated and "ready to use". In fact, abstract artists often use canvas that is not "ready to use" and has not been coated. 
If you want a colored background, buy a bottle of Gesso to coat the canvas with a touch of color. This layer will dry quickly.
- Choose your paint. Determine whether you want to use acrylic paint or oil paint. Acrylic paint does not cause odor and is easier to use because it can dry out quickly and can be coated with paint if you make a mistake. However, oil paint is usually not used because it smells, takes longer to dry, and you cannot coat it if you make a mistake.
- Collect brushes and other tools. Choose whatever brush you want to use for use with the paint you have chosen. You can also use a palette knife to paint, to produce a textured look. Although some artists like to use buffer wood, many abstract artists choose to put their canvas on the floor just so they can be closer to the painting work. 
If you are not sure what color can match one another, consider using a color chart or wheel. This can help show which colors match one another.
- Wear your painting clothes. Depending on how messy the painting you are going to make, you better change clothes with an old shirt or upholstery to paint. Without worrying about paint staining clothes, you can focus more on the abstract art painting or process.
You also need to put a few sheets of paper to prevent paint droplets or spills, especially if you plan to paint by flicking a brush or putting canvas on the floor.
Thanks you by @rafael-timo