Spear first, tomahawk second and knife third.
The spear sticks without figuring out any spin because with a spear there is no spin. Cold Steel has a nice spear head
http://www.coldsteel.com/fixed-blades-bushman.html that doubles nicely as a knife. You fix it onto your own shaft. I use Maple since I have plenty on my place. The blade metal flexes and you have less chance of breaking the blade early in your hurling.
The tomahawk has more heft and more sticking area. It is soooo satisfying when it sticks due to the mass involved and the violence of the impact. Choose the heaviest hawk you can throw. I use hawks made in Canyonville by a terrific craftsman whose name escapes me. His goods are sold at Mountain Man type tables at blade/gun shows. The head is reinforced against breakage by using a bimetallic head. The head should travel down the handle so you can replace the handles as you break them. And, you will break them so get at least one replacement handle.
The knife, hardest to stick IMHO, is a real joy to set into a target from a distance. I use Gil Hibben's largest, Bowie style, all steel knives.
http://www.knivesplus.com/hibben-throwing-knife-uc-gh455csnb.html Choose the heaviest you can throw. It helps to have a smooth handle to slip from your hand as you hurtle it. Love them.
To stick the hawk and knife: Try throwing from various distances and when you stick measure this distance as your successful throw distance. You will find other intervals of distance for sticking based on revolutions of the thrown weapon. The interval will probably be different for a hawk vs a knife as each rotates at different speeds (unless you cleverly compensate by spinning the weapon appropriately).
Having several helps keep walking to the target down to a minimum. It also continues the fun, because you have another weapon, when you can't find what you just threw away.
All the best,
oregon