Do what the best sellling new IP this gen (and of all time) did.  Bundle it with the console at launch and advertise it like hell.

yep they are 1st party studios owned by sony and apart of SCE World Wide studios like team ico (SCE studio japan) etc etc 

Don't release on the same day or week with another big franchise.

Well MM weren't owned by Sony at the time of LBP 1's launch I believe; but Sony with work with "2nd party" studios like Sucker Punch and others, which they don't own, but have exclusive contracts with

Anyway, I think releasing August or September is the best thing, but also launching early in the generation. Quality wise, Uncharted 1 is not that much better than Enslaved, yet Enslaved is barely selling and Uncharted sold 3m (there was some bundling, but it would have got to around 3m anyway), the difference was timing; Uncharted was earlier in the generation and also Nate sold a few copies....

The easiest way is huge amounts of advertising, and making it something truly unique, like Assassin's Creed or Gears of War (it was almost new at the time, even if it's been copies loads since)

I think the biggest problem with third party new ip's is the fact that they usually try to wrap a new shell around game mechanics that are already in established franchises. This is a shame because a new ip poses as the perfect opportunity to try something new and different.

Best Way to release a new IP is

1)For it not to suck

2)Release it by itself away from other games

3)Actually advertise it

That's the key