Amy, my heart goes out to you and unlike some people, I understand the wanting to quit. First thing, don't compare your work to magazines, they have been shooting for years with a Hasselblad camera and the latest Post Production software. Just stop driving yourself mad
I started out 14 months ago with the same frustrations. First of all, when you are taking a pic of an entire family, it never looks good at 100% so don't freak out. Only couples or singles should look sharp at that zoom. Second, your shots are a bit grainy, I had problems focusing a LOT until recently. I did the focus and recompose junk, and the half-press shutter focus. The bottom line is that TOGGLE focusing worked for me. If you need help on this, just google it or let me know.
OK, main things to worry about as a new photographer...IMHO
#1 ALL photos look bad SOC (unless you are the 2% of pro photogs that have that special touch) so just worry about exposure and focus ONLY.
#2 Auto focus is JUST FINE! Just learn to get your focus point to the face or the center of the group
#3 It just takes TIME and lots of practice. I wanted to quit 10 times in my first year, so don't worry, just keep going
#4 There is a LOT of information out there, and it all says different things. The answer is, there is no right answer. Just what is right for your camera and for you.
#5 Rule of Thumb - Aperture should be a minimum of 2 full stops higher than your # of people (ie... 5 people, f7.0 minimum! but I prefer f9.0)
#6 Once you learn all the rules, feel free to break them for your art!
http://www.sarahreidonline.com
when I started 14 months ago, I did not even know what aperture or shutter speed meant. I have learned so much and am so excited to learn more!!!