Join the IRSP comrade. They have been reorganising and have now become very active.
Join Eirigi, RNU or the 32CSM. All three are good socialist groups cara, the rest of the left in the occupied six aren't very active and they don't address British imperialism well enough. They are also hesitant to condemn blatant loyalist sectarian marches and they don't take to the streets enough for pan-left protests.
Sorry forgot the IRSP there, they're very active around the Belfast area. I'd join them myself but am in Dublin and they don't have much presence down here.
I'm a huge supporter of Sinn Fein and I love the SP