Passing is definately tough on Heisman and its easily the hardest part to deal with on this level. Awareness is on 0 so I can't even drop it further. The only think I will say is that its very important to determine whether its man or zone at the beginning of the play. You should also watch where the safeties are. For every passing play I run, I try to call a play where there will be someone running a post or seam route. If its man-to-man, you can usually pass the ball to a WR or anyone really if they are open. Watch the safeties and if they cheat up (especially before the snap) you probably have a blitz as well as 1-1 with a DB to that side. The post (WR or TE) is usually open in front of the safeties and over the defenders in the short zone.
Against zone, you can hit some drags and crosses or dump it to your RB out of the backfield. You can even hit some slants between zones but curls are deadly and not worth the risk - too many picks. The post route is easily the best way to beat a zone but you have to hold onto the ball longer than in AA. You really have to wait for the player to clear the LB (who drops further than AA and quite frankly cheats a bit) before you throw it. It helps to put a little touch on it but generally throw the ball hard to avoid their super closing on the ball.
Plays like Ace Slot Deep Outs are good because you have a post route in the middle of the field you can hit against a zone and deep outs to the WR (wide side mainly) against man. Roll outs can really help you get time to find holes in zones. Plays where you can roll out with a WR deep and the TE on a corner are really great as the TE should be wide open (I form: PA Boot, Ace Big TE WR: PA rollout). You just have to be careful for the strong side DE - if he is a great player you can get sacked on these plays (throw it hard to the TE).
Seams to slot WRs and TEs can be open too against the zones. The CPU plays zone the majority of the time so get used to it. Practice against zones to figure out which plays work for you and which don't (many). LBs are super aware on Heisman which can get frustrating. The pass rush will get you but just accept it and don't rush your throws - throwing too early will only lead to bad plays. Simply wait for the guy to be open or take the sack. Avoiding turnovers is important on this level. Covering up on the ball when in a crowd is a must to avoid fumbles on Heisman.
I really enjoy playing against the CPU offense on Heisman and I like the human running game better on Heisman. Special teams are harder but I have broken off a couple TDs and I find better than the ease of AA. Its the human passing game that will make or break your love of this level. Just work at it and try to get the ball into the hands of your best player or best matchup. If anybody else has any good plays that work well on Heisman, please post them here.