If there's one thing that takes many first-timers by surprise, it's the physical size of Comic-Con. When you look at the programming, and see facilities described as "adjacent" and others as "2 blocks away," it all sounds so manageable. If you need to hop from a panel in 28DE to the Indigo Ballroom or the public library, you'll just hustle and make it happen, right?
Not always. Just meeting up with your friends within the Exhibit Hall can take longer than you'd imagine. You're in Lobby A, they're down by F, and you've got to fight all kinds of crowds and strollers and lines and cosplayer clusters to reach them. Or maybe you're traveling outside - and you didn't realize how long it would take just to cross the street, (see below) let alone navigate the blocks to the Horton Theatre.
Here's something that can help: looking at an aerial view of the convention center like this one.
That's the center in the middle. To your right, you can see the Hilton Bayfront where the Indigo Ballroom is. On the other side of the convention center is the Marriott Marquis, where quite a few panels and film festivals are, and rising up beyond it is the Manchester Grand Hyatt, home to the blood drive, the daily Conan Pop giveaways and other events. From looking at this, you can tell that a basic hustle isn't going to cut it in all cases. So factor foot travel time into your plans.
One way to save yourself a lot of walking and a lot of time: mapping out where your panels and booths are in advance. Look at the convention center floorplan just to get an idea of what you'll be navigating. Just seeing the room capacity can help you put lines in context. If 6BCF holds over 2,000 people, a line down the hall isn't that foreboding. But if you're trying to get into room 8, which doesn't even hold 500 people, then maybe that long line is telling you to go elsewhere.
As convention centers go, navigating San Diego's is fairly intuitive. I doubt you'll get lost. More likely you'll just underestimate how much time you'll need to get hither and yon. That may not sound like the most dire fate but it can ruin an entire afternoon when you miss getting into one panel and it's too late to backtrack to your second choice. If you're new to SDCC, find some time to walk around when you arrive. You'll get a feel for it all and get a better idea of how to plan your day.