1. The cast. 
Bradley Cooper is great as the teacher recently out of mental hospital and trying to get his life back on track.
Robert De Niro can really do comedy, as he demonstrated in Meet the Parents. This is his best and most comprehensive performance since Casino.
Jacki Weaver was in Russel’s last film and makes a great foil to De Niro’s intense and hyper-kinetic book keeper.
Jennifer Lawrence. I hated Hunger Games and didn’t make it to the end of Winters Bone. But Lawrence is right on the money, Her arriival in the film’s first half hour takes it up a gear. She
plays 
Her scenes with Cooper are a joy to watch. My favourite? The glorious dance scene where she shows him how to waltz to Bob Dylan’s The Girl from the North County.
3. The dancing
I love any movie where actors you wouldn’t imagine dancing are made to strut their stuff. Jennifer Lawrence looks beautiful and sexy dancing alone or with Cooper. The last scene of the dance competition is my favourite moment of the movie, even if they’re aren’t the best dancers, their soul and passion are what matter.
4. References to other great films
In showing Cooper how to dance, Lawrence shows him a clip of Gene Kelly and Donald O Connor tapdancing in Singin’ In The Rain. This is incorporated in the final sequence. Any film that mentions Singin’ in The Rain earns points instantly,
5. The film’s trueness to life
I never felt like what I was watching couldn’t conceivably have happened to people somewhere, That doesn’t happen when I watch other films,
6. The characters
I liked all of them, Even the older and more successful brother, who by rights I should have hated, I didn’t.
7, The black mental patient
I can’t remember his name but he was hilarious. He should be in more films.
8. The music
David O Russell uses music to heighten our emotional response, or in some cases, simply because he just loves the song. Whatever, the music is great, look at how he uses Arctic Monkeys and John Coltrane in the same scene.
9. The Script.
Woody Allen used to be the go-to man for witty, literate films about New Yorkers, Not anymore, If Silver Linings doesn’t win the best screenplay next year, something is very wrong with the world.
10. The overall mood of the film
There is something very warm about these characters. You want to spend time with them and therefore you keep watching the film because you care about what happens to them. This is why films which are character led rather than plot driven will always fascinate us more. Again, a few american directors have always known this, Russel is continuing the freewheeling narrative flow that began in the seventies with Hal Ashby comedies and John Cassavetes realist dramas.
There doesn’t seem to be much else on show at the moment, My advice is to see this straight away.