The main problema with your portraits are the light, composition (they're all posed in the center of the frame), and a lack of understanding of depth of field. You're going to need an external flash and you'll need to learn how to use it, of course, if you hope to shoot portraits.
For your first portrait, you moved the young lady into the shade, which is good, but you didn't add any light to her and your DOF is too shallow.
For the second shot, you have the couple facing the harsh overhead sun. Rarely will you get a decent expression on your subjects under these conditions. DOF is good.
Your 3rd and 4th portraits, you don't have your subjects facing the sun, but you have the sun hitting them on the side of the head with their faces in shade. Get them out of the sun and add a flash.
Your DOF is good for the 3rd shot, but too shallow for the 4th one.
Your last portrait, you have the sun at their back, but their faces are in deep shadow and need additional light on them. Here a shallower DOF would have been helpful to blur the background building.
Except for the last image, you seem to be getting nice expressions from your subjects and most would have made nice portraits with the proper lighting, DOF and a little better composition.
There are a number of inexpensive 3rd party flashes out there that won't cost you a fortune and I think acquiring one should be your first step if you're serious about shooting portraits.
You have a fast lens that can shoot very shallow depth of field images, but make sure to allow enough DOF to keep your subject's facial features in focus.
"Google" "portrait photography" under images to get an idea of compositions you like. You'll probably see quite a few images placed dead center in the image, as you've done with yours, but those won't normally be the best images.
Keep practicing and have fun with it. Don't rush going pro since your clients may not be happy with your current work and that could hurt your reputation for future business, when your photography skills improve. Good luck and enjoy the journey.
BTW, if "John's Creek" is the one in the Atlanta area, I believe they have a number of Photography Meetup groups that could prove very helpful to you. Most Meetup members in my area are always happy to offer help with anything that may be giving newer photographers problems.
Canon 7D, 5D, 35L, 50 f/1.4, 85 f/1.8, 135L, 200L, 10-22, 17-55, 70-300, 100-400L, 500D, 580EX(2).
Sigma 150 macro, 1.4X, 2X, Quantaray 2X, Kenko closeup tubes, Yongnuo YN685(3), Yongnuo YN-622C-TX. Lots of studio stuff.
** Image Editing OK **