Longer than you think - astroNikon, that's a realistic description of it. And what Lew said, these seem to have similar need for improvement as the first set, not all sharply in focus and exposure probably needed some adjustment (the one of the tunnel looks like it might be focused behind the little boy instead of on him).
There's more to it than can probably be explained in some posts here to learn how to set ISO etc. Every time you take a picture basically you have to set the camera for that particular situation (existing light etc.) although if the light isn't changing you might not need to adjust the settings as much. To compose images think about what you see in your viewfinder, if everything you see is what you want in your picture and is where you want it.
I don't do much photoshopping but I'm a longtime film photographer so probably learned how to get the photo I want in camera most of the time, so do minimal editing. There's potential in your photos, like a lot of things it will take a good bit of learning and practice to get good at it.