I think the grass and ferns too need that white outline - and the floor plane is too painterly - you've still got a mix of styles going in here - try and imagine that everything in your world has been made from the same stuff and cut out in the same way. You need to rationalise your style further (and I don't quite understand the smudgy 'sun ray' - even the sunbeam - if you want one - should be a paper-style cut-out - an actual component.
Thanks Phil, I'll add the outline to the grass. As for the floor plane, the idea behind the painterly effect to the floor plane is because it is printed on the book. Hence, nothing is gonna happen to it. As for the sun beam, because I want the attention to focus on that particular set of ferns (As there are many others on the page) It would be like a fold out from the clouds to show the beam. Having said that, it has not been successfully portrayed and I will work on that. Thank you :)