I have watched up to the episode of "Q-Less" in season 1 and i'm just wondering if I could skip to season 3 (the war stuff) without missing too much?
The "war stuff" doesn't really start in season 3, that comes later in the show. The only differences between seasons 2 and 3 are that the Dominion reveal themselves and the USS Defiant is introduced. In fact, some fans (including myself) believe that season 2 is slightly better than season 3 overall.
Then there's me who thinks season 2 is vastly superior and one of the show's best. The eight episodes leading into the season finale was the longest run of consistently excellent episodes in DS9's history.
And all in all, season 3 is is a pretty weak season by DS9's lofty standards (its weakest after season 1 IMO), so I wouldn't be rushing to get to it. And to make matters worse for arc fans, the Dominion storylines were by far its weakest aspect. With the obvious exceptions of Improbable Cause and The Die is Cast, the Dominion episodes in season 3 ranged from - at best - average to downright awful.