How do I get my pictures to look like this?

alot of practice,lessons and equipment :3

practice, practice and even more practice! I can't do it like that (yet) and I always get so frustrated ^^"

Well of course lots of practice and also that pic looks like the person drew it on the computer so it depends on how well you can draw on the computer, what system they used like Paint sai or Photoshop.
When you get the hang of drawing the colouring is different because there's many ways of colouring and shading.
Also you could go on Youtube and look at tutorials or speedpaints to help you get an idea of how to and keep trying you'll get there sooner or later or something like that because everyone has their own kind of art style

they probably have the help of a computer....

practice.