What I've done: Just been checking my contacts, making sure they aren't too tight. I'm currently on my 6th set of aligners! About halfway there!
What I'm feeling: The last set of aligners felt a bit tight for a little longer than the previous ones. I am thinking that this is just because of the movements that each aligner takes you through. Some aligners may have more subtle movements, while another may take a tooth in a new direction. Teeth are naturally allowed to move (which is why orthodontics is possible!), but every tooth can be different in how quickly it moves. As long as the aligners eventually get easier to take on and off, I know that they're doing their job of moving teeth into their new position.
Progress: I've recently received some comments by people who know about my treatment, that they're starting to notice change. I've been told that my front upper incisors are straighter (woohoo!). Personally, I've noticed my lower incisors pulled in a little, and I also notice that my upper incisors have rotated some as well. It feels good to see the progress! I will probably take pictures in the future to post here. Stay tuned!