New to bicycle maintenance

...SIS, which I know is probably just of a passable quality. The chain still feels a little lose around the front chainring. It still pulls off a little bit if I tug on it. However, the teeth on the sproket do not appear to be very worn or anything (well, they are nice and long, but they are not as squarey as the teeth on the rear cassette, but they are longer/taller). Can you give me suggestions ...