I've also been wondering a lot about this. There are certain key dates/events between now and Episode VII that Lucasfilm/Disney can use to make big reveals/announcements either about this film or the spin-offs:
San Diego Comic Con: July 23-27
Star Wars Celebration Anaheim: April 16-19, 2015
Star Wars Day: May 4, 2015
San Diego Comic Con: July 8-12, 2015
D23: August 14-16, 2015
Not to mention New York Comic Con, Wonder Con, C2E2, etc.
With the prequels, Lucasfilm announced the titles anywhere from 8 to 10 months prior to the release of each film. If they stuck with that timeframe, Celebration Anaheim would be the ideal place to reveal the title (perhaps as part of a trailer).
However, I have difficulty believing that they would wait
that long to announce the title. It's a different world now from when the prequels were released. The voices of the fans are "louder" due to social media. Maybe Kathleen and JJ actually could "ignore the noise" that long, but I'm sure our lack of patience would be made
very clear to them.
Therefore, I'm gonna guess they will reveal the title and character names at Comic Con...maybe an appearance from some of the cast? (If they really are flying the Avengers cast in from London, they can all share a plane...

)
I think a teaser trailer will be debuting at Celebration Anaheim. A final trailer will debut at D23. Comic Con 2015? I dunno...footage, maybe?
(Obviously, I'm just throwing stuff out there...who knows, really?)