This is my second cruise. My first cruise was a 3 night cruise with Celebrity Infinity from San Francisco to Vancouver.
Embarkation: We got there around 1:00pm. They said boarding starts 1:30pm but I think quite a few people have checked in prior already. I recommend getting there early as you can get settled and start enjoying the ship. Also be prepared to get a bit lost finding the pier. It might be because I am not familiar with the geography of the area, and did not do enough homework but I had a hard time locating the right freeway exit and got quite lost. The area looks quite industrial and it may be a bit intimidating once you go off-route. Look for Queen Mary sign, and a sign (and I believe just one sign on the side of the freeway) that mention which exit is for passenger cruises. Have everyone in the car watch for you, as there's quite a bit of signs.
Parking - use their parking lot there for $12 per day. There's no other parking options around within walking distance unlike some of the other ports. And of course you can always take shuttle or other forms of transportation there. Getting on is quite smooth. Our check in rep is a bit slow and sleepy, but rest of the reps seem to be friendly.