Step 1: Slice beef
Cutting the meat when it's well-chilled (or even frozen) helps to get nice even slices. Don't fret if you can't see through them; just do the best you can at cutting them thin.
The cut of meat you select isn't terribly important; just try to get a decently-sized cross section for your slices. I've also used bison roasts to good effect.
Step 2: Marinate with brown sugar and garlic
Finely chop a large handful of garlic and place in a prep bowl. Fill another prep bowl with a couple of tablespoons of brown sugar.
Designate one hand for meat, and one hand for toppings. This should make cleaning up raw meat-contaminated things much easier.
Sprinkle the bottom of the bowl with a layer of garlic and sugar, then add a single layer of beef slices, making sure not to overlap.
Sprinkle with more sugar and garlic, then continue alternating layers of meat with sugar and garlic.
Place bowl in the refrigerator for at least one hour; overnight is fine as well.