Lucky Block addon - is all about win or lose and there's nothing to rely on except luck. All you'll need to do is to find pigs (they will be replaced by lucky blocks) somewhere around or to spawn them manually, using spawn eggs. Then you will need just to destroy them using hand or some tools, they will drop either nice thing or will do you some harm - that's depends on how lucky you are. Among the items that have a chance to drop are: diamond tools and armor, iron tools, wool, villager, creeper, explosion, enchanted armor and etc.
Mod were updated, drop rates was changed a bit, now it's harder to get really valuable items and explosions happens quite often. I advice you to destroy them from the distance, using bow - it will make the process of testing your luck much safer.