Just note down things that you see are visibly not normal or sound unusual. Make a list of it. If you have someone knowledgeable about BMW you may ask them to have a look. Main things are engine sound, transmission how it feels when you drive.
I just went to my dealer (Mississauga BMW) and they did all the oil/fluid changes. They even fixed my vent tabs that were broken. My washer fluid tank had a minor crack and that was fixed too. I also paid some extra $ to do some additional work: flushing of fuel injector due to mileage. The car purrs like a pussycat now
If you are still not sure what to do, just drop by to the dealer service and inquire from them as to what will they be doing on your car as per the warranty. If you do not like anything they say, you can always explain and/or eve speak to their manager.
Do not wait until couple months before the warranty expiry - you want to get the max out of it. Hope this helps