Good start on shooting manual! The first picture looks a little over exposed and IMO a little too much water showing. Both of these issues can be fixed in post production. When I started to shoot in manual, my instructor told us to bracket the shots. So we were taking 3 shots of the same subject and shooting +1/-1 exposure inaddition to the correct metered exposure. This is just so we could see the difference between them. Your camera may also have an auto bracketing take a look at the manual and while you're looking at it look for metering modes.
Your second pic is very symmetric. Meaning it's very balanced on the left and right of the subject. I think if you used the rule of thirds and crop, it'll look even better. What you did correct that most newcomers wouldn't do is use the shade. It looks like afternoon to late afternoon in the pictures and that would cause some harsh shadows. Try using your flash to brighten it up a little or edit it after. Also, I see something that I used to do a lot and sometimes still do. Do you see the leaves coming out of the subjects head that look like antenna? Try getting lower or separating the subject from the background to blur it out a liitle more.
The third pic is a great example of the rule of thirds... Actually it's an example of why the rule doesn't always work. I think this is your best shot! Although it's a little under exposed, you have a great subject with very engaging eyes. Great texture in the background and a good contrast of textures between the subject and the background. Once again Great Job on this shot.
The last photo is also a great shot! The only thing I would do is to crop out the road. This shot would make a great aquascape.
I hope I'm not too discouraging on the comments. But believe me, I have hundreds(probably thousands) of photos that needed work when I started. What's really cool is to see the progress I made year after year. Keep it up your off to a good start.
P.S. Hey Do you mind me editing these pics in Lightroom to see what a little post production can do? I'll erase them after I'm done. If not, I understand.