Well it looks to me like you’re well on your way here and there isn’t anything I can tell you that you don’t already know about photoshop!
My favorite image of the three is the danger keep back sign. That’s a really lovely image aesthetically and you showed restraint in creating it. The image of the sunflower is also quite stunning!
Photoshop is very powerful and it’s easy to create tacky things with it. In terms of photography it’s best to do subtle tweaks and make simple fixes with photoshop.
I generally do most of my work in Adobe Lightroom just because I find whenever I go into photoshop I go overboard. With great power comes great responsibility…
I recommend you take some time to learn Adobe Lightroom if you haven’t already. Here are some Adobe Lightroom videos.
Nice work here you are really doing great! 🙂