After a few years of living in Boston I have now endured the apartment hunting experience twice. The first time I was looking for a room and roommates in a place near Harvard Law School where my fellowship was located. The second time I started looking for a unit with my girlfriend in Southie. These were different experiences that both turned out to be tougher to surmount than I expected. However I learned there are things you can do to set your expectations and make your apartment hunt go smoother.
Looking for roommates and an apartment is challenging because you are trying to get the kind of unit you like and find a group of people you will fit in with. When I was in that situation I went to about twenty showings and was rejected by most of them. Competition is fierce and you can only gleam so much from a first meeting. The most important thing is to be persistent. Furthermore, you should prioritize the roommates over the dwelling unit quality. However, if you can find roommates first and search for a dwelling unit that might be a better way to go.
If you do that you get to learn about the world of brokers. Brokers can work for buyers or sellers. You want a broker that is working for you. The way you find a broker that works for you is you go to a Zillow open house and ask if the broker can help you access other properties. They have access to the MLS. You can then work with them to schedule showings and try to get approved for a property.
Knowing these things is not going to make apartment hunting easy, but hopefully will make it a little easier.