It will vary from weapon to weapon, but you need to take the time now, before you get into the field, to insure your gear is in top notch condition. This would be a good time to stop and take a look at your current physical and mental conditioning. Time to take a few rounds and make sure you are familiar and ready to the kick and noise. Flinching even one inch out the barrel, can throw your projectile off by several feet in the distance of 200-300 yard shot. Make sure you also are using the same ammunition that you will be hunting with.
Ammunition changes in the middle of a hunt can also lead to a missed trophy.
Physical and mental conditioning and just as important as the expensive set of camouflage gear you wear into the woods. Being familiar and comfortable in your surroundings is important. You need to know where animals are likely to enter into your shooting lanes and know the distances you are capable of shooting successfully. Get out now, before the season opens, if possible, and get into the areas you are planning on hunting in. Write down times you spot game, locations, and sign that animals have recently been in the area.