Basic rule of thumb given to me by an old timer (possibly one of Rainboe's ex colleagues) when I converted to the 744; 10kts x-wind? Hold 1 unit (control wheel aileron trim indicator) of into-wind aileron; 20 kts-2 units etc. and that's right from the start of the takeoff roll. That, together with a smooth and slow(ish) rotation rate seems to work pretty well, followed by standard basic technique of centralising controls once airborne, as already pointed out.
Different case on landing in strong gusty x-winds when more aggressive work is needed to keep the wings level and avoid a pod strike (over 7 degrees roll in a typical extended flare will put you in that territory). I was surprised how eager that big wing is to start lifting when the winds blow.