Understanding more about painting watercolours

After following martha's poppy class and learning such alot I still knew there was masses more to learn. I decided to copy a print I have had for a long long time in the hope I might learn more. I certainly did. Most importantly I learnt I must mix up enough of the main colour to see me to the end. As you can see I didn't, then I realised I must let parts dry before painting in something right next to it. Now I know I need to get something (I don'tknow what its called) to paint on where I want white to stay,and that I can't paint over where I've already painted because the colours mix so.
I was sorry I messed up one of the middle flowers petals, but overall it was well worth doing. I am going to try the same approach to leaves next,then will try again to paint real flowers from the garden.