-- Pat has given you some good pointers and she has a good eye.
I think you'll find the corrections quite difficult however. Take it from me ........ I'm noted for making corrections all the time.
My suggestion for now would be to concentrate on the background on this piece of paper so that you'll have a better idea for starting over. (Something we all have to get used to doing.)
Dampen the whole BG all around little Roo with clear water. Then, with colours you think appropriate (mixed quite strongly ahead of time), pump them into various areas and let them blend themselves. Perhaps some blues at the top, sea greens in the middle, and maybe some weak burnt sienna at the very bottom (your choice of course). Leave some of the areas white and the colours will work their way in as it dries. As long as it is all still wet you can add more paint .... but don't scrub or mix. The less touching the better! It's best if the colours blend thenmselves gradually but still maintain their original hue in places. (Some people like to add bits of clear water to the odd place to get some neat effects but that will come with experience and confidence.) Let dry thoroughly. If it dries too light (which is usually the case) you may have to rewet the whole area and drop in more of the same colours in the same places. Best if you don't have to do that though. Get lots of colour in there the first time ..... and keep in mind they always dry lighter.
You'll end up with a pleasing BG with a minimum of work. Do it right and you'll get the impression of a beach scene where the BG is out of focus. But if it doesn't look like a beach, don't worry about it. You'll be thrilled you have a great looking BG done already.
When you feel confident enough to try the painting again, print off a copy of the photo, correctly sized to your watercolour paper. Rub lots of graphite pencil all over the back of it to create a carbon paper. (You can get jumbo sticks of graphite at the art stores and save on the pencils.) Tape it to your watercolour paper and trace Roo's features with a ball-point pen so the graphite transfers to the wc paper. Do your BG as above and then concentrate on your painting of Roo. Remember the things Pat told you.
Hope this all makes sense.