First off, the clarity loss can be due to either high iso film (gets grainy) and/or wrong camera settings. Also Wal-Mart is not exactly the best place to get your pics done. Then, scanning takes out a lot of the quality, I know from experience.
What I'd recommend is, like Max said, to read up on it. Of course you'll learn most things you'll know from practice, but just a little background can be useful when you start.
Does your camera have a light meter? If so, then trust it, it's always helpful. However, with time you'll be able to figure out the right exposure by yourself.
The one thing with film photography is you have to know what does what. I mean how a variation in each parameter will affect the picture. Once you get it, it all becomes very clear.
Also, I've been having very frustrating experiences with a flatbed scanner. If you think you'll be doing a lot of photography in the future, consider getting a negative scanner. The image quality loss is very low and easily fixable with any editing software.
Now about the pictures. What was your film's iso? Looks like 200 to me, but I could be wrong.
They could definately use more detail in the shadows. You can get a higher iso film. 400 is considered all-purpose and I think it could work fine here. 800 would give way too much grain and you'll lose a lot of clarity.
Other thing you can do is use a larger aperture (which is designated by a smaller number... took me a while to get this when I was starting) or a slow shutter with a smaller aperture which should give nice contrast.
However, I should add that if you said you made the pics intentionnaly the way they are, i would've believed you because the colors give a very special touch and a sort of retro feel to them. #6 and #12 are very catchy with the lines. With some minor level adjustments on the computer, you should be able to get them to look fine.
So, all in all, for somebody who had no idea what they were doing, you did rather good.
Keep shooting, read up on it and you'll be getting great very soon.
again, try to get your negatives scanned instead of the prints.
good luck :thumbup:
ps: also I should add that most of this type of photography is done digitally, ususally in automatical mode :er:. Hence the clarity. So I give you a high-five for doing what you do. Film, esp in manual mode, is more challenging, but much more rewarding. so keep at it.