Originally Posted by TN Lone Wolf

Calls: I like to have a grunt tube with me. Not to call them in, but rather to stop them for a shot.

When to hunt: I've found the best times are the two hours after sunrise and the two hours before sunset, although it doesn't hurt to hunt a lot longer. The main thing is to get in the stand or blind fairly early. For example, at least 30 minutes before legal shooting light in the morning.

Shot placement: Depends on your angle. Since you're using a 243, I would recommend waiting for the classic broadside shot and aim midway between the top and bottom of the chest (or a bit below that point) just behind the front legs.
{I removed the images because I have less than 10 posts and can't post URLs yet because of that}

Bullet rise/fall: With a 243 sighted in at 70 yards, you don't have to account for bullet rise/fall until you start shooting close to 200 yards. Aim the same way at 10 yards as you would at 100, and everything in between.

Adjusting your aim from a treestand: At rifle ranges, you won't have to worry about it.

Bullet choice: Woo boy, you've opened up a can of worms here. There are as many opinions on that subject as there are bullet types and weights. My answer would be use what shoots best in your gun. Either one will quickly kill a whitetail if put through both of its lungs.

Originally Posted by MudderChuck

I wouldn't get brain lock, there is really no substitute for the real thing.

Take a good solid rest, relax, good sight picture, control your breathing and squeeze the trigger. Once you get to the point where you can shoot a decent three shot group, give it a try at extended range and even different angles/elevations. Good form has a lot more to do with good shooting than trying to overthink it. And remember it has little to do with how many bullets you fire, much more to do with how accurately you fire every bullet. Consistency is the key.

Try it at different ranges and even from a high seat. A flat shooter like the .243 and "aim off" really doesn't figure in much until you get out to extended ranges.

Any of the top brands of ammo/bullet are going to get the job done. Shot placement is a lot more important than finding the perfect bullet IMO.