Scalping tickets on game day is bad advice. There was an epidemic of fraudalent tickets that went around here some years ago. It would be terrible to spend your hard earned cash on some genuine looking tickets that turned out to be frauds or even stolen..
Secondly, scalping tickets will probably not get you the seats you want. most of them will be in the nose bleed sections or at angles you dont even want.
Being a gambler and a huge NFL fan across the board, i am one of those weird people who would rather stay home and watch multiple games on two or 3 screens than waste an afternoon watching the titans from the nose bleed sections..
If you are looking for good tickets where by you wont get ripped off (be ready to spend quite a bit over original price originally) then i have a simple trick for you to establish relationships with credible scalpers.
Simply go on ebay, find a guy selling tickets in your local area, email him before you bid and tell him you want to meet him in person to pick them up..
(You have to make sure he has multiple listings of tickets...there are several ebayers of this calibre for practically every team in the NFL at least)
Once you find your guy, either place a bid or contact him via email to buy some off him and inform him that you will bring him more business...
I did this last year (paid 300 for Titans vs colts home opener) needless to say this guy who had several friends with psls would call me first every time one of them was looking to scalp tickets... I tried contacting him this year but both his emai and phone are gone...
I have already found another guy who seems to be one of those full time scalpers and he gave me all his contact info and he will sell me good tickets for far less than the 250 i paid him for this years Titans vs Ravens.
Thats the best way to make good contacts and in your local area too. (I wouldnt recommend out of state scalpers)