Well first you'll need a flexible tape measure. You need to take measurments on the deer to buy your mannikin. Measurment "A" from the tip of the nose to the front corner of the eye. Measurment "B" get the smallest measurment of the circumference of the neck directly behind the ears. Measurment "C" measure the circumference of the neck about 3" below where you measured the "B" measurment. I get a more accurate measurment of the neck after I skin out the deer. Get a note pad, and write down all measurments

Your going to need a good skinning knife, and sharpener
A scalpel to split the eye's, lips and nose.
Ear openers
A bone saw of some kind to cut off the antlers
A fleshing machine, or a draw knife, and fleshing beam to flesh down the cape.
Salt to salt down the cape after fleshing
Needles and tread for sewing. I use 20lb. Spiderwire fishing line for sewing my capes. A good 3 point needle, regular needles for sewing small cuts. Also get a sewing palm. It'll help in the long run, when you have a lot of sewing to do.
A staple gun of some kind
A tack hammer
Scissors
Grooming brushes
Latex gloves for skinning out your animals
Small bubble level
Rasp, good wire brush for your mannikin prep
Drill
Lip tucking tool, I made mine out of a old paint scraper
Hacksaw blade for cutting the lip slot
Some kind of mounting stand
Screw driver, I use a rounded off screw driver to remove the cape from the antler.
Hot melt glue gun, and glue skicks
And get as many reference photo's of deer, The nose, eye's, ears, and all around photo's
Hair setting gel
Pins, T-pins, mounting pins
Drywall screws
galvinized brads, a brad setter
modeling tools
Clay, I recommend getting some "Critter Clay" For modeling the eye's, on the nose, and I cut a small grove in the back of the mannikin and fill with clay, where I'm going to sew up the cape. Then tap the stitches down into the clay when I finish sewing.
two part epoxy, like Apoxie sculpt,
If you're going to do the Bondo type ears, you'll need Bondo, the hardener, and fiberglass chop, and fiberglass layup resin
A good hide paste
Hide puller
Super Glue
Awl
I would recommend getting a Skiving knife for thinning the lips and eye's.
Brushes, Utility, acid, paint brushes. If you're going to use an airbrush, then you're going to need a compressor, with moisture traps, and a air regulator
Paints, I keep a different supply of oil paints, Acrylic's and lacquer base paints
Some kind of heavy plastic, I use a plastic garbage bag for this. When your putting on your hide paste to the mannikin, I cut out a strip of plastic and put this on the mannikin where I'm going to sew up the cape. When I'm sewing the cape I'll pull out the plastic little by little until I'm finished sew the back of the cape. This will prevent the hide paste from making a mess on the cape, And a lot less cleanup in the end.

This will get you by. You'll figure out what else you need, when you start doing more heads. Good Luck to ya.