Aside form the various techniques, which will no doubt seem strange, pay attention to the overall "vibe" of the dojo. Are people smiling? Do they appear to be enjoying themselves, or are they laboring thorough one tedious exercise after another? What is the ratio of talking to practicing, etc...After all, it's supposed to be enjoyable and enriching, rather than just another chore at the end of the day. Osensei himself said that Aikido should be practiced in a joyous manner, just like any other art form.
...although, speaking for myself, I have to say that the things that appeal to me now are not the things that would have appealed to me as a newbie. So, yeah, you do want to look to see if the people training seem happy (which doesn't necessarily mean goofy-smiling all the time), and not so much at what
they're doing -- which, as Karl says, won't make sense and probably won't seem too enjoyable to you right now.