How can I be more out going?!?

I have always been so shy! I don't really know why, but when I'm alone or meeting particular people who intimidate me (probably about half of people) I get scared and don't know what to say. I tell myself I don't care what people think, and I don't but I can just never think of something to say to someone I don't know very well most of the time. I don't want people to think I'm unfriendly or cold or something, but I just really struggle with being outgoing. Tomorrow im starting a New Class and i have nobody I know in the class or atleast not well. How can k prepare myself to make friends? Should I come in late so I am forced to sit with someone I don't know? I don't want to seem like I'm trying too hard. Help!!