Give me your honest opinion

  I did more of it , sorry for any confusion  
Im using Autodesk Sketchbook 
Im using premier marker 
Im not sure what other tools to use 

OK, honest opinion... I'm not sure what you are doing exactly. Just practicing in general or trying to finish something? All three images you have posted so far have been unfinished, but I'm not sure if you intend to continue working on them or are just trying things out.

I kind of feel that to give good and proper feedback I need to know what you are doing.
I would like to know what program you are using. And what brushes. It looks to me, so far, as if you mostly use something like an airbrush and most things are just diffuse and blurry. You did use a harder brush for the shadows in the duckling picture, I believe. Valence gave you some good advice for colouring pages of lineart: to set your (new) layer to multiply so you don't need to worry about overpainting the linework. I think I would also suggest that you make an "underpainting" of flat colours with a hard edged brush, and then select the areas you want to shade, e.g. a cats eyes, and use a soft brush on a new layer, within that selection. (Or just paint on a new layer and then select the flat colour area (old layer), inverse the selection and delete the paint outside of the area (new layer).)

I think you need to be a little more patient with your work. Try to commit to finishing a picture instead of switching quickly to another one.
As I said before, set your line layer to Multiply and paint on another layer underneath and start off by painting over all the white. A blank white canvas can be so intimidating when you begin a picture so fill it with a mid tone, any colour will do but if you're uncertain then a blue grey will keep things neutral. Then you can start painting into it. First just choose some mid tone local colours and block in all the subjects of the image with those flat colours. Again, be patient and control the edges and once that's done then you can start introducing lights and darks to make things more three dimensional.