|Ultimate is an offensive sport. As such, it is expected that throws will be completed. The cost of an incomplete throw to the offense is very high; it can cost 2 points, since in an offensive sport it is assumed the offense should score each time. As a result, throws should be conservative - flat, low forehands or backhands to open people making hard cuts. Of course on occasion longer or more challenging throws must be made, but after each one, whether complete or not, it is a good idea to ask, "Was that a good selection?"
To complete a pass, a thrower ideally needs two things to exist: a receiver must be free from his defender, and there must be a way to get the frisbee to the receiver. This path can be up in the air, as in the case of a high curve or a hammer, but normally an offense should stick to high-percentage passes: straight, flat forehands and backhands. In these cases the disc needs to go down a "lane", a region of the field where there are no offensive or defensive players to interfere with it.
Most teams now run a stack, or some variation of it. The stack basically works by clearing out all people from near the thrower and letting a single receiver cut in that space. This way, whenever he gets open from his defender there is by default a passing lane, and the disc can be passed to him.
stack analysis (warning: biased)
The idea of a stack as main offensive set is a "new" development in Ultimate that apparently became popular when I was out of the US in the late '80s. Before that offenses would usually try to spread out as much as possible, creating holes in the defensive coverage that could be exploited by the cutters. (stacks were used in specials circumstances - for instance, Princeton's goal-line "foreplay" was basically a stack.)
The Empty V is based on the Princeton offense we played 1976-80. At the time we did not analyze it this way, but inherited it from the earlier players, who got it from CHS (I guess), and honed it evenings at the club moving around coins on a table. It had no real name, since we just called it "the offense".
I had advocated it instead of the stack ever since founding the Beijing team in 1996, but due to blatant stackism and my inability to describe the offense concretely got little hearing. Credit goes to Jud Wilmont for making me think how to describe it without waving my hands around.
The idea behind the Empty V is to invert the stack paradigm: rather than have a stack of players there are 2 lanes (antistacks) forming a V in front of the thrower which are kept open. A cutter times his cut to get open inside one of these lanes, fulfilling the 2 requirements stated above to complete a pass.