Tips for mixers and networking events in grad school?

So I just started grad school in the US and would like to hear some tips on how to best approach mixers and similar types of networking events with both students and professionals.

My issue is that I don’t really know how to start conversations when there is no one that I know with whom I feel comfortable speaking to. Sometimes I may also be acquainted with someone, but may feel rather awkward like starting a whole conversation.

So what advice do you have for these types of situation? especially for breaking the ice and actually getting to know new people at these events (and taking advantage of the same).

For more context, I would say that I generally have good social skills but these kind of events where you are on your own, so to speak, throw me off. Also, I feel that some cultural elements might be at play. For example, in my country we don’t really have networking in the US way, and another example is that it can be considered impolite to simply “jump” into a group that is having a conversation.

Thanks in advance.