Besides all the pre-hunt prer and practice, practice, practice, Be very patient.
Allow the bear to come in a few times. They like to run in knock the rock off the cover, grab a piece of food and run out to eat to the side so let him get relaxed before you shoot. He'll come back in. Unless of course he doesn't run to the side and offers ya the perfect shoot.
As above posts, my brother while rifle hunting took a bear at 80 yds that looked real big in the field. The way the fur stands up came deceive you as to the size. Got back it was only 60lbs. :(
Use the drum which are typically cut in half as a guide. There are some great tapes out there.
Black flies, if their there you will know it without good netting.
One final important note, if the outfitter packs you a lunch to take with as mine did at Slipp Brothers which I highly recommend, keep it high in your pack.
You wouldn't want one climbing up the stand your in to get a bag you let by your feet.