What type of hours did you pull?
I poured every possible waking minute into studying, especially first year. I did spend some time on leisure and family, but I tried to literally use every minute studying, to the point of studying on the can. I was married with a kid when I started, and I had my wife on board, so that made things easier. If your spouse/significant other doesn't understand the time commitment to get into some of the more competitive specialties, you'll have a rough time.
What kept you motivated?
I wanted to specialize from the beginning. I knew that this would involving paying for everything on the front end, and reaping the rewards on the back end. In other words, dental school would be grueling, but after getting into my chosen specialty I would be able to have more balance and would have a more enjoyable career, for me. This has already turned out to be true in my residency.
How did you deal when you slipped?
I never really "slipped," but I definitely got extremely stressed out at times, and would worry myself sick over grades and "what if I don't get in." I had set ambitious goals and I definitely felt fear of failure at times, and also thought, "What if I don't get in, and I wasted all of this time and effort?" At those times I reminded myself that general dentistry is a fantastic field and would provide me with a great career and lifestyle, and I'd already achieved that! Everything else was just icing on the cake. This helped me let go at times that I was sawing sawdust and worrying over small things.
How do I increase my lab speed so I'm more efficient for training for practicals and projects?
Practice, of course. Read The Talent Code by Dan Coyle - there's some really enlightening stuff in that book, especially when it comes to the role of practice and mistakes. At my school, usually if you did decent on practicals you could make up for it didactically, so I got good at practicals, but by no means was I even close to the best in my class. Nailing the written tests was my strength, so I still got A's.
For speed, try cutting some crown preps ridiculously fast for a dental student - like in 5 minutes, or a bridge in 10 minutes. Pour stone models of your typodont and practice blazing fast preps on the stone models if you don't want to waste a bunch of money on typodont teeth.
Make sure to get as much feedback as you can from professors - don't just hide out in the corner and get by! Get feedback from every professor you can because every different angle you can approach your work from will help.
Any other words of wisdom?
Don't underestimate little classes. The difference between being ranked 1-10 often comes down to 1 or 2 B's, even 1 credit hour classes.
I found flash cards to be incredibly helpful. I figured out how to print them on my printer and would make stacks of flash cards when appropriate and review them all the time. One of the biggest strengths of flash cards is that it's easy to separate out the things you don't know and focus on them. Your knowledge doesn't increase when you review things you know over and over, and you're also wasting time if you're not focusing hard on what you don't know.
Set specific goals and write them down.