The first two darings were for an assignment to design a book cover using digital illustration. It was aimed at young teenage girls and I wanted them to give a scrapbook look, similar to the Lola Rose cover by Jacquline Wilson
There are lots of books out there which will teach you basic drawing skills such as perspective and anatomy and such like.
Also look out for online tutorials on You Tube etc.
Most importantly, though, get yourself an A4 sketch pad and sit and sketch what is in front of you - a shoe, a vase of flowers, your mum watching tv, whatever. Or look out the window
and sketch what you see, with emphasis on "sketch" - don't worry about shading or colouring to start with, and keep them small. With figure drawing, start by doing a cartoon version
of someone running or whatever, then redo it by making it a bit more realistic each time. Try and do something every day, even while watching tv, for instance.
I agree with practice. Mainly because you lines lack confidence, and if there is something that an illustration needs it is confident lines. you definitely have a really good grasp on the general feel of, in this case, children's book illustration. But children specifically need something to aspire to in an illustration but for it to look not too good so that it alienates them. You are well on your way