I know you have loads of mediums that you’re not sure how to use.
Try one of my 'how to' videos, just visit the ONLINE LEARNING page.
Have a go at a colour wheel;
Visit the Colour wheel tutorial https://triciajohnson.wixsite.com/tricia-johnson/post/gouache-colour-wheel
download the simple colour wheel and follow the instructions in your chosen medium. This is a great way get familiar with a new medium without the pressure of completing a finished painting.
Get a feel for mixing, consistency or mark making by completing the colour wheel template.
Don't forget to share your results with us all.