Northern Ireland in the Political Landscape of the UK is an oddity to say the least. Generally Northern Ireland is left to it's own devices and the Major UK parties take a slim interest in the power struggles for Stormont.
The Tories, Bless their cotton socks do make a small effort when it comes to Northern Ireland, They run a few candidates during assembly elections and occasionally link up with the UUP. (Though the UUP+Tory formula does not equal results) If the Tories decided to make a concentrated effort on Northern Ireland they could possibly take a few seats. To get seats though they would need to decide how they would squeeze into the battle;
UUP: The UUP going into 2011 will have a brand new Leader, Zero Westminster seats and no momentum going into the Assembly Elections, Perhaps the Approach Cameron should take is Being the Vulture to the UUP's Corpse, Take the Centre right members of the UUP for the themeselves and leave the DUP and TUV to fight over the leftover Unionists.
Sinn Fein: A difficult plan but it would really depends on how the Tories played it. Cameron has expressed his dislike for McGuinness so it would probably appeal to Cameron to dismantle Sinn Fein's Power. If the Plan of Attack was to point out the Irish schools issue and EU Agriculture Fine as examples poor governance by Sinn Fein and combine it with drawing focus to the fact that during the Recession Sinn Fein spent money running a general election campaign when they had never any intention of taking their seats and back it up with shots on Expenses which Sinn Fein drew Universal ire from every other party for, Cameron could shift support to the SDLP. Admittedly going after Sinn Fein would serve to to weaken an enemy rather than gain Cameron Seats but in the long run it could remove Sinn Fein from politics and allow more Tory friendly parties to take the seats at Westminster.
DUP: The Big Dog in the yard and probably the best left alone, with the DUP having the TUV barking at the doghouse and the Robinson saga they would be in no mood to dance with the Tories.
SDLP: Simple one, the SDLP are the Labour party of Northern Ireland, so if it's played just like that the Tories could then argue to be 'Normalising' politics in Northern Ireland.
In the end they will just have to run and hope.
Labour on the other hand haven't ran candidates, there are Labour parties just not the UK one. I think attempting some sort of official Deal with the SDLP (and possibly Irish Labour party) would be their best bet, creating a Labour Party of sorts of the whole of the British isles would win alot of fans on the left and allow for policies to be calibrated to maximise their effect over two economies.
I personally would love to see one or two seats won by the main parties, I think it would make the assembly more interesting and nudge Stormont towards mainstream politics of the UK.
There are three obstacles in the way however, Sinn Fein, The DUP and Fianna Fail. The DUP will not like the idea of the two big British parties playing in what is effectively their domain and will most liekly fight with everything they have to prevent any victory, Fianna Fail who are setting up shop in Northern Ireland will not be warm to even more competition to the voters they are trying to woo.
Just a little speculation on my part...