Think about what you want in a dojo. Different schools have different priorities. There are dojos that focus solely on tournament performance, while others focus more on real world self defense. Many other priorities exist such as schools that focus on just sparring and those who do no sparring but focus on kata. Decide what you want out of your dojo.
Beware of McDojos and Belt Factories. These are terms used in the martial arts community for karate schools that are over commercialized and where it is unreasonably easy to attain new belt levels. Some ways to tell if you've walked into one of these is, how many very young blackbelts do you see? If there are a lot of them, it is probably a belt factory where the dojo's focus is on charging fees for belt tests as often as possible. Another sign of an over commercialized dojo is if the uniform turns you into a walking billboard. Having a patch or insignia to represent your school is fine, but having multiple patches, or your whole gi covered with advertisement could be a sign of over commercialization.
Look for signs of healthy living habits. Does the instructor participate too, or just shout orders from a seated position. Is the instructor 40 pounds overweight? Do the instructors bring in a big greasy pizza every time a student is promoted? If the answer is "yes" then the instructors are not practicing or modeling healthy living habits.
Beware of the Kobra Kai! Many people think that the villains of the original Karate Kid movie are unrealistic and over-the-top. Unfortunately, they're all too common in American Karate. If an instructor acts anything like the villain from that movie, stay away!
Do you like the style of martial arts being taught? This is an important question to ask yourself. Styles of martial arts are numerous and varied. Some styles focus on wrestling, while others do stand-up fighting. If you like Shorin Ryu, here are some other styles that are similar.
Ueichi Ryu, Kung Fu, Chuan Fa, and Ishin Ryu.
If you're going away to college, start a martial arts club! Older students who go away to live on campus at a college have a unique opportunity. You can start a martial arts club. This does not mean becoming the lead instructor of a campus dojo. That would be too difficult for under-belts. What many of my karate friends did when they went away to college was start a club where martial artists of any style can come together, train, practice, and perhaps even spar. This is relatively easy to set up and it looks great on your resume to be the founder of a club in college.
Again, I hope you stay with Shorin Ryu, but if for some reason you are forced to change things up, I hope this information has helped.