I've been attending Otakon for 18 out of the 20 years. I hope to be there this year, as I want to attend the Yoko Kanno concert. A little about me, I've staffed many anime conventions, have staffed Otakon in the past, so I kinda know what to look out for when and where.
I'll give you a complete breakdown.
DO NOT LOSE YOUR BADGE!
First off anime prices are YMMV. Dealer tables cost money anywhere from 500-$700 a table, so these dealers need to make money on their investments. I'm a fan of supporting the industry, but I am also a smart shopper. When buying something, ask yourself do you really really need it. Is it something you will watch/play a lot, or is it something that will take up space. End of the day it is up to you how you want to spend your money. If you see something, make note of it, there are hundreds of dealers, so keep looking around. Odds are strong you will find another dealer selling the exact same item but cheaper someplace else. Also keep an eye on your items, especially at the dealers room. It's very easy to misplace an item and find it missing. It happened to me last year when I put down the Excel Saga blu ray that I bought. 10 seconds later, it wasn't there.
If you have preregistered for the convention, I suggest you arrive on Thursday to pick up your badge. Do not wait on line, go pick up your badge around 7-8pm. There will be no line and you should be able to just walk in and pick up your badge. I've done this for the last 4-5 years, and it has never failed.
If you MUST pick up your badge on Friday, expect a 3 hour wait. The line will loop around the entire convention center, which is about a mile long, from 1 end to the other. It will be hot outside. If you are prone to heat stroke or can't stand out in the sun longer than an hour, than I suggest you take a walk around the inner harbor. It's a tourist attraction. Come back to pick up your badge around 12-1pm. The lines should be gone and it will be more manageable.
Make sure you are wearing comfortable walking shoes. Your feet will hurt by the end of the day with the amount of walking you do. Some of the escalators will be turned off due to weight restrictions. Otakon attendees average more on the heavier size so some of those escalators can not handle that weight. Make use of stairs or the elevators.
Make sure to always have water with you. There are water stations in all the panel and video rooms, but there might not be enough cups, a water bottle can help fix that.
Big events like masquerade, concert, autographs, will have a line. Be prepared to arrive 1 hour early for autographs, 2 hours for Masquerade and Concert. Please note there will be 2 concerts. One on Saturday afternoon, the other on Sunday. Not sure when on Sunday.
If you have a smartphone, download guidebook. Otakon will release their schedule a day or two early. There are a lot of things to do, so do plan your day out.
For food, the inner harbor Is great for cheap mall type food. There is also another mall across the street which has cheap but tasty noodles. If you want to do a sit down restaurant, there are plenty of restaurants nearby. My favorites are the Edo Sushi place, Tir Na Gog (irish bar/restaurant) and La Tasca (love their sangrias and paella). I do recommend the local restaurants like Phillips if you are into seafood, and The Fudge Factory. This is where the R&B Group Dru Hill was discovered....(I think)
For drinks, on Thursday night go to the Power Plant and enter the Howl at the Moon. They have dueling piano bars with singers that take requests. I usually try to get them sing "What What in the Butt" as made famous from South Park or Electric Six's "Gay Bar" song. for $5-$10 you can also take a water taxi to the other side of the harbor. There is a bar there that has 100 beers on tap. The place is called Max's Taphouse. Take a cab back to the hotel but keep an eye on your drive. Some of these cabbies will take a 5 min ride into 15 mins to try to price gouge you. I guess they know when a tourist is in town.
For late night entertainment, from about 11-2am, Otakon will have a dance, it's more like a rave party. You can also walk down Baltimore Street for the strip clubs which close at 2am.
Otakon closes at 2am, most restaurants close at 2am, the mall closes at 10-11pm. Pizzerias close around 2am. So your only food options after 2am are the 7-11s