I have free time in college, unfortunately there is nowhere people-less I can go. I have my guitar connected to a pod with earphones, so I have that covered.

I've heard that there are silent metronomes, which rely only on visual cues. Can anyone recommend me a good one?
Nearly all of the electronic metronomes I see have some sort of lights and / or bar graph display that also shows the beat. Even the ancient electric one my wife has for piano has a light on top that flashes with the beat. The only comment I would make is that I find these really hard to use - I spend more time looking at the light than I do worrying about my playing. I find it a lot easier to use some very simple downloaded looped drum tracks at specific tempos instead of an actual metronome. My brain says that it should be the same with a metronome or a drum track, but I much prefer the latter.
I wouldn't bother with visual unless I had no choice.

The sound is there for a reason, it's a lot harder to sync up visually if you're not good at it.

Play along to music, that's what got me timing. Focus on hitting each note on time.