Photoshop is part of my photography process, and I love to do what I can to make my photos look as good as possible. Nothing too dramatic, just a few subtle tweaks here and there to make them pop.
This (very simple) tutorial of sorts is what I've found works for me; I have to put out the disclaimer that your results may vary...but in the end, it's all about trial and error and experimenting until you find something that's tailored to your own needs.
Here's the original image, straight out of the camera.
Image > Adjustments > Auto Levels
I've found that, depending on the lighting of my photos, Auto Levels can completely screw up the colors. In those cases, I'll use Auto Contrast, which basically does the same thing but without altering the colors at all.
Image > Adjustments > Levels
These are the settings I used. Of course, you should experiment with the sliders to see what works for you. The black arrow controls the darker shades, the white arrow corresponds to the lighter. Slide the black towards the center to make darks darker; conversely, slide the white to the center to make lights lighter. Center arrow = midtones; slide towards the black arrow to darken, towards the white to lighten.
I'm guilty of abusing the Levels tool a bit, but I just love the heightened contrast it creates; none of that washed-out vintage look for me, thanks! ;D
Before and after levels adjustment:
Layer > New Fill Layer > Solid Color:
At this stage, sometimes the photo can look a little 'cold,' so I warm it up with a layer of yellow/orange/rust. This is what I mean by cold; if I could go back and edit those photos to make them a little warmer, I definitely would. As it stands, though, it's a lesson learned. Warmth is happy and friendly and inviting; cold, not so much.
Before and after fill layer:
And that's it! It really doesn't take much more than minimal effort to make some subtle edits -- that's really all you need for nice, natural, professional-looking photos.
Here's the overall before and after again:
If you have any questions, feel free to ask! :)