Talking about things that have been in the news recently can be a good way into a conversation... mention something that has interested you in the news recently and ask them what they think. You could ask them about what they intend to do after college, what their long term plans are... People quite often like talking about themselves, so ask them questions about these sort of things and perhaps stuff that they enjoy doing, have done recently... things like that.
If you are doing the same degree as someone else, talking about that course could be a good way into a conversation. Find out what it is about the course that interests them and you might be able to carry on talking from there.
Perhaps another good hint is not to try to hard. Try not to appear desperate for conversation as this could put people off. Try to appear friendly and, if they talk to you, interested. Don't forget that most people struggle to find things to talk about from time to time, so don't feel you are alone in feeling awkward in social situations.
Hope this helps... good luck! =)
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We beat on, boats against the current, borne back ceaselessly into the past.