Welcome to the forum Sarah.
Glad to see the rudeness of some didn't scare you away

.
I am right on the verge of transitioning from hobbyist to semi-professional (but will always remain a hobbyist who loves to shoot for my own pleasure).
I came to this forum knowing very little, and have learned so much from people here (as well as taking courses in photography). It is really a worthwhile forum, just ignore the snarky comments.
The most important piece of advice for composition that I got when I started was:
1: Choose a theme for the photograph, ie. what is the subject of the photo? What do you want people to see?
2: Focus attention on your subject
3: Simplify the subject and photo. Remove any unwanted or distracting elements, like power lines or objects that make the eye wander from the subject.
Of course the next thing is look up different links to understand how to use the rule of thirds, and I believe that the iphone has a rule of 3rds overlay that you can use.
And next is the most difficult part, learning lighting and exposure. Unlike having an eye for photography, which generally comes naturally (and is exceptionally difficult for people who don't have it to learn it), and it appears that you do have a good eye, lighting and exposure can definitely be learned, because it is a science (there are also art aspects to it, but first learn the basics of the science, and the art will come).
Best of luck with your hobby (new or not) and best of luck fulfilling your dreams.
And just remember, photography is one area that IS legal to shoot people for fun and profit, and won't get you sent away for 10 - life (in most cases

).