Having fun is the best advice. I will add something to that, remember that 3D is not bowhunting. In other words, you will find a lot of guys that have bows set-up just for the competition. There is nothing wrong with that, if you want to be a champion at 3D mainly, but if your focus is hunting, shoot your hunting bows, with quiver attached if that is the way you hunt.
I know a lot of guys who bring out the binoculars, and carry picture cards of the kill zones. There is nothing wrong with this either, and I would recomend it if you want to be a 3D champion, but I perfer to shoot them like I would if I were hunting. That will not give you the highest score per target, but it will get you ready of hunting. Unfortunately, not all kill areas on 3D animals are located in the best place to put the arrow when killing is your goal.
It has been stated above, very well I might add, that you should not worry about what others are doing as far as score. Let your first shoot be your starting point, and attempt to get better from there.
While I don't shoot as many of these as I once did, I averaged about five a month for ten years, I never exclude my personal hunting practice, that is purchasing my own 3D targets and placing them in areas, creating senerios that mimic the hunting I will be doing.
I am of the opinion that anything that keeps a bow in your hands 12 months out of the year is a positive, putting you way ahead of most bowhunters. Don't neglect the practice of shooting in the woods where you don't have a perfect view to the target. Learn what the trajectory of your bow is at different ranges, learn to shoot kneeling, sitting, leaning, from an elevated position, and even from your belly. This is not likely to happen at most 3D shoots or ranges.
What a lot of us have done is to purchase a target or two each, set up some treestands, and ground blinds on a mini range. We then go through and pick different shots, follow the leader. Sometimes we keep score, sometimes we don't, by the time the season rolls around, we are sharp as tacks. This is not a subsitute for 3D competition, but an augmentation to your hunting.