Color mixing seems to be a serious problem with a lot of artists. I have decided to start this post where I can every now and then add something about color mixing as a help in learning this skill - because this is what it really is - You have to make the time if you want to progress properly. I have a lot in mind but I do not want to overwhelm you with too much at a time - that would be counter-productive. So let's begin at the beginning.
If you want to play the piano then you have to learn the notes first


This is a chart that I made up of all the Paint Basket colors that was available to our franchisees. The most important part of painting is to get to know the tonal ranges in the painting even BEFORE color is added. Think about it! Here you can see the tonal range of each separate color.
Make yourself a similar chart with all the tube paints you have in your paint box. Group similar colors together for easy comparison. The chroma color straight out of the tube is added to the top block and the lower three have white added to them progressively.

This is a close-up of a portion of the above chart. See how much easier it is to see the comparison between the adjacent colors!

This is a sample chart of what you can learn by the methodical approach of mixing colors. Here Viridian (Pthalo Green) is my main color and the various colors that can be obtained by mixing other colors with it. If you want to learn to mix quickly then don't neglect this exercise. I have many sheets similar to this in my file for reference.
Explanation: Let's look at the bottom section of this chart for convenience sake. I have used Viridian and Raw Umber in the first set of vertical columns. Make a 50:50 mix of these colors and place it in the middle of the second set of vertical columns.
Add a small portion of Raw Umber to Viridian and put this in the block above the 50:50m mix.
Add a small portion of Viridian to the Raw Umber and put it in the lower block.
For each of these second mix of colors add white progressively to the last two sets of vertical blocks as shown.
This can now be done between various tube colors until you have exhausted all the combinations you can get out of you paint box.
Make this a fun lesson(s). Enjoy.
"Don't take life too seriously, you will never get out of it alive
"