honestly so far as I seen you definitely got the basics down, now it´s only left to master adding more depth to the work, details to the skin, or make the fur more prominent on Vi, etc.

How do you think I could add more depth and fuf detail? ^^;

http://www.furaffinity.net/view/14847500/ <-- a small example of adding small fur details, notice the lines on her body and the small patches of fur "sticking out" helping to create the feeling that she has fur and doesn´t look like just coloured skin.

http://www.furaffinity.net/view/14809288/ <-- another such example as well as a example how important shading is to give a "3D depth" to a character

http://www.furaffinity.net/view/14724524/ <-- another lovely example


also tho just a personal taste but I prefer characters with defined muzzles and a more animalistic facial structure, like the above examples.