What I learned when I completed this colour chart.

I have to admit, I thought it was a very straight forward exercise. But it gave me a surprise! 

I sat down at the table with out any plan in my head. grabbed some colours and went at it! I rushed it and it was a mess. But it didn't have to be! So, to make it easier for you, here is what I learned:
The printed colour chart before I painted.
My very first piece of advice and the most important is this: Don't rush it! Block out a morning or afternoon. Make yourself a cuppa coffee or a glass of wine (if its after 11am somewhere). And make sure you will have no distractions. This is your time to immerse yourself into the process, enjoy the calm repetition like you were meditating. I think this is the most important part of colour mixing. 
The second piece of this perfect recipe is the colour choices. You do not have to pick the primary colours and secondary colours. You can use your favourite, most used colours or you can pick a theme. But what ever you choose, balance them. Balance light, medium and dark colours. Put them in order. One being the lightest to seven being the darkest. Also consider if the colours you are choosing art cool or warm? If you spend a little time curating the chart, it will be incredibly satisfying at the end. Every colour will bring you joy! 
Be careful and patient when mixing the colours! I made the mistake of trying to mix them inside the square. This didn't result in a very balanced chart. Start with one column, one colour and on a separate paper or tray mix that with a little of the matching colour. The most important aspect of this step is control and constancy. You want a medium saturation and a 50/50 mix. If you do a 20/80 mix on one, then a 60/40 mix on the next, the colours will not have an even, pretty gradation. 
Lastly, enjoy it. Do not despair if you make a mistake. Remember, its just paper. Finnish it with all its mistakes and take everything you learned in this journey with you. An artist only grows when they make a mistake.