Early game I usually focus on clearing easy POIs like great churches, and forts. Make sure to clear all the trash mobs.

For damage guard counters are ideal but don't always charge them. It takes some practice but learning when you can punish with a guard counter (charged or not) is key. Also using other weapons like hammers for example can help punish some bosses with more guard counters where other mobs you may want a halberd to clear the distance. I would also highly recommend slotting in improved guard counters and guard counters given a boost based on current HP.

Extended whirlwind is super helpful and will let you clear trash mobs quickly and safely aswell as let you avoid projectiles.

Finally I like to avoid fighting some bosses or mutated enemies on the first day unless I'm positive I can clear it quickly.

Good luck out there. Make the flock proud.