Improving my photography (pics)?

I love taking photos of my daughter and I'd like to improve.
I'm using a Nikon D3100 and the basic kit lens.
I've taught myself how to shoot in manual (thank you youtube). Now I've just started using photoshop. Just for basic brightening and some sharpening.

What would be the next step to improve would you say?
I was thinking maybe I should start with getting another lens. Any recommendations?

Here are some photo's I've taken. Please offer some constructive criticism but don't be to harsh as I'm just a beginner to the DSLR world.

Taken outside:

Taken inside

They are pretty good try looking up different effects you can add and learn more in-depth editing and shooting skills in the way you want it to be