Prepare Materials: Make sure you have all the materials you need ready, including various tubes of paint, a mixing palette, brushes, solvent (like turpentine or an odorless solvent), and rags for cleaning.
Please read the notes below...
Choose base colors: Decide on a base palette of colors that includes the primary colors (red, blue, yellow) plus white and black. You can also add some extra colors to expand your palette.
Arrange colors on the palette: Squeeze small amounts of the selected colors onto your mixing palette. Place them so that you have enough space to shuffle.
Plan mixing ratios: Think about the shades you want to achieve and plan the mixing ratios in advance. Adjust the amount of colors used accordingly.
Mix colors: Start with the base colors and gradually add more colors to get the desired tone. Use a clean brush to blend the colors well. Be sure to mix enough paint to achieve an even consistency.
Add light and shadow effects: To add depth and dimension, mix in a darker color for shadow effects and add a lighter color for light effects. Make sure to create subtle transitions by gently blending the colors.
Do test swings: Before you apply the mixed paint to your canvas, do a few test swings on a separate piece of paper or canvas to ensure you have achieved the desired shade.
Clean your brushes: Thoroughly clean your brushes between color blends to avoid unwanted blending. To do this, use the solvent, rinse the brushes and dry them thoroughly.
Experiment and Practice: Mixing oil paints takes practice. Experiment with different color combinations to achieve the hues and effects you want.
I wish you a lot of fun!