Outside of the hunting aspect - proper hydration was an issue the first time out for me. I was in a spot that had plenty of clear, cool, delicious spring water - just didn't drink enough.
100% on the slowing down. I didn't get busted by a cow but by a trailing young bull last time. If I would have been paying more attention I could have gone around or THB he was legal and still being a virgin I probs would have just shot him.
Also if there is an obstacle and its between trying to move around dead fall and crunchy leaves and giving a toot on the cow call - maybe try the cow call, esp if they're in range. I think that you have a better chance of moving them 2 feet then having to move yourself 20 without them disappearing or getting busted.
Double check your maps downloaded to your phone properly before heading out if you don't have a hard copy. Man does that suck.