Watch this video. You can read more into the details elsewhere, but this video gives you a good idea of what to do.
I'm averaging 55-60MPG in my Gen2 (only a couple smallish tanks and the bladder in the tank makes those inaccurate, too). The Gen3 should get a few MPG higher than the Gen2. My technique is to accelerate at a moderate pace, generally about the same as traffic, not charging or discharging the battery (or doing so just barely). At speed, I pulse and glide as much as I can. You should never have to use neutral, just let off the gas and slightly reapply it. This should kill a warmed up engine and provide no regen or assist from the battery. coast down 5-10MPH depending on traffic, then use the same moderate acceleration to pulse (maybe just little enough to charge the battery a bit). I usually use cruise when warming up (can't P&G) or when traffic or speed won't let me P&G. I keep the AC usage to a minimum, especially when P&Ging because it drains the battery fast, limiting glide length. I try to slow down just by coasting, but that usually isn't possible, so light braking to stay keep from using the friction brakes (you have the little bar that tells you how much regen you're doing, I think it starts using friction brakes when full). Only shift to B if you're going down a large hill (like L in most other cars). Always be aware of your surroundings and keep other drivers happy and safe.
As for mods, an easy and effective one is pumping your tires up to sidewall max. Hopefully it came with LRR tires.
Are you measuring your mileage by the computer or at the pump? 50-54MPG is already above average for 2010 Prii on Fuelly. It takes some time to get used to the way you need to work the Prius. 60MPG tanks shouldn't be very difficult for you to get when you know what to do.