Chances are very good that there will be help close by or at least available - help defined as someone with previous deer hunting, and handling, experience. It is best to be prepared, though, even if the novice is hunting with a platoon of Daniel Boone clones.
Experienced deer hunters with the Arkansas Game and Fish Commission offer a first suggestion: After the deer has been downed, after there is no doubt about it being dead -- wait. Stay some more minutes in the tree stand or in the spot of firing the shot. Just wait a few minutes. Sometimes even a fatally hit deer will jump up and run or try to.
Then, decide if the carcass should be taken to camp or to where help is available whole or field dressed. High up in this decision is how quickly can it be cooled so the meat doesn't spoil. This is a key factor in winding up with venison to be proud of on the dinner table.
If moving a whole carcass is in order, forget any notions of throwing it over your shoulder and walking out of the woods. This doesn't happen unless you have killed a 50- or 60-pound deer. It doesn't happen even if you are a weight-room legend and starting left tackle on the football team.
To move a dead deer, you drag it. If it is a doe, turn it on its back, step between the two hind legs, grab one with each hand and walk. If it is a buck, use the antlers for a handle and drag if from the front. Your belt or a short piece of rope you've brought along becomes most handy here.
Field dressing is a polite term for gutting. It means to remove the entrails of the carcass. Should the decision be to field dress, go with it. You have to have a knife. It doesn't need to be a Bowie knife nor a pen knife; a sharp knife of most any sort will work.
Roll the carcass on its back and begin at the neck. Make one firm but shallow cut through the hide and hair from the neck to the back end. Start the cut then pause and work two fingers into the opening. Carefully keep the knife blade between your fingers and use the fingers to keep the hide away from organs inside.
What you must avoid is cutting into the intestines. Make this mistake, and the meat may be ruined for eating. Especially avoid slicing into the bladder near the finish of your cut. When the cut is finished, pull the opening as far apart as you can. Here, you may want to take off jacket and shirt, down to a T-shirt.
Then reach in at the neck and start pulling everything out, all the way down to the back end. Messy? Yes, it is. But it has to be done.
When the organs are out, check inside the cavity for anything else than needs to come out. You'll have to cut the windpipe loose with the knife. If grass is handy, grab a couple of good handfuls and wide the inside - or use some paper towels or toilet paper that you had stuffed in a pocket.