Worried about Difficulty?

Hey! I’m currently a junior, and I’ve been thinking about college a LOT lately. I’m worried about being able to pay, and most of all…even getting in. I don’t have a lot of extracurricular stuff going on, but I have joined a club this semester, and I’m gonna do a bit of volunteer work. I’ve been going to my local community college full-time since last fall, and by the time I graduate I plan on getting an Associates degree in Math. What else should I do? How can I increase my chances on getting into a good college with decent aid?