>>2607087If your photo is about a moment, and plane of focus and freezing motion aren't particularly important, use P mode. If your plane of focus is important, use Av mode. If stopping motion is important, us Tv mode.
If you don't know much about composition, do a quick read about the rule of thirds and that will get you started and keep your photos competent enough to avoid many issues. And remember, when you take a photo, think about whether your viewer will be interested in it. You might really want to take a photo of a stop sign, or a bush, but you may come to realize (hopefully) that nobody will care about looking at that photo (including you in a month). It's good to practice, and shoot for yourself, but a good photo requires a good subject.