Look at this phaser design:
Why this design? Okay, it is very compact, but aiming precisely with such a thing should be almost impossible. Is there a reference where this design explained or justified? Maybe these devices aim themselves so no precise aiming is necessary. Who invented this design? I guess this guy never tried to aim with a handgun.
Phasers are not meant for anticipated combat. They are personal defense devices for away missions. As such, they don't need to be super accurate.
There are two raised bumps on the phaser just past the indicator light.
Based on the way we see people firing these, you point it at arms length and perhaps aim with those two ridges.
Based on these images, the beam it produces is slightly lower than what you are pointing at (I blame the FX people).
You can also make the phaser beam become wider, requiring less accurate aiming.
If you are intending to go into actual combat, such as later during the Dominion War, you use a phaser rifle.
The stock and scope both lend themselves to pinpoint aiming.
Within the TV series, we see that the Type-2 ("dustbuster") phaser is basically a line-of-sight device. You wave it in the direction that you intent to shoot, press the button and the phaser beam emits in a straight line until it hits the target.
The Star Trek: Voyager Technical Manual explicitly states that there is no computerised targetting on the smaller hand-phasers. You aim simply by pointing and shooting at the desired target.
Since there's no obvious aim-point on the phaser, using them accurately would require a high level of familiarity. Within the show, we see various officers practising with their phasers in order to learn how to aim them competently and with precision.
The TNG Technical Manual describes the amount of target shooting practice (e.g. monthly for away-mission candidates) that is required before personnel are allowed to use phasers. We can reasonably assume that there will also be minimum range scores before you can go off the ship with a weapon.
Wherever the beam goes
Concerning specifically the "hand vacuum" style which was popular around Picard's time, and not the more pistol or rifle stock variants, we should remember that phasers have one specific advantage for aiming over your standard bullet tosser:
They are beam weapons.
This means that unlike firing a bullet at a target and you have no idea where the shot will land until it actually collides with something - phasers give the wielder constant feedback as to where the energy is being targeted.
Or to put it another way, you would aim it the same way you aim a laser pointer.
Admittedly, I am coming to this debate rather late, but it seems everyone is overlooking a simple and obvious solution: Phasers used LASERS for aiming.
Although not demonstrated on screen, it seems logical to assume that all phasers from TOS to the present could generate a simple laser beam to indicate the impact point of the phaser beam. Phasers 1 and 2 are sidearms, used for close quarters and would not need a more complex sighting system. Phaser rifles all have some variety of optic or electronic sighting system to target at ranges beyond a visible laser dot.
Perhaps phaser 1s and 2s have two-stage triggers - a light depress activates the targeting laser, and a firm press fires the phaser.
Lasers were new science when TOS aired and were large room-filing devices so even though writers could imagine immensely powerful hand held phasers, they couldn't make the leap to conceive of REAL laser technology being so compact.
I have read many posts pertaining to phaser aiming and have not seen anyone else propose my solution. Assuming anyone revisits this topic here, I would be interested in hearing their opinion of my solution.
