weapons

As predators, vampires have many advantages over their prey—much more than they really need. They have many weapons which they use to catch their prey.
The physical appearance of vampires is enticing to human eyes, which lures in their prey, making them vulnerable to attack.   The speed at which vampires can move is exceptional, and means that a chosen victim could not escape if a vampire wanted to attack them.
Also, the vampires can obtain superhuman strength, which allows them to effectively catch their prey. 
Aside from a vampire’s strength, speed, and physical appearance, there are other advantages that vampires have over their victims. One of these is smell; a vampire’s breath will even lure a human to them. Their breath is described as being sweet, delicious, and mouthwatering—pulling their victim towards them, so that they are entirely vulnerable to attack. It’s hardly necessary though, as vampires are so strong and fast that a chosen victim couldn’t escape anyway. 
Instead of having fangs, the vampires have razor-sharp teeth. Combined with their strength, it is not difficult for them to rip through flesh to drink the blood of their victims. 
The vampires are also venomous. But, the venom will only pose a danger if it runs through the bloodstream. It is not acidic—it will not harm the skin. But, it will infect an open wound—and from there, it can its way to the bloodstream, and that is where the danger lies, because a vampire’s venom is what causes someone to become a vampire. 
Along with all of their other weapons, vampires have extremely acute senses; they have much better hearing and eyesight, as well as much larger hearing and eyesight ranges. Also, their sense of smell becomes much keener. 
Some vampires have extra senses, or additional weapons, that allow them to have even more advantages over their prey, and over other vampires. In Twilight saga so far, Edward, Alice, Jasper, Aro, and Jane have been recognized as vampires with such additional weapons. Edward can read minds—human and vampires alike, with one exception—Bella Swan. He hears the errant thoughts running through the person’s mind at that certain time. But, he can only hear the thoughts of the people around him—there is a distance limit as to how far away someone has to be in order for Edward to still hear read their mind. Alice has visions of the future, but she can only see the outcome of a decision, not the thought process behind it. But, her power has one exception as well—she is unable to see any visions involving werewolves, and if a decision is somehow related to a werewolf, Alice’s vision will disappear. Jasper can manipulate the mood of people around him—he affects the physical body, slowing the pulse and upping the endorphin levels to calm someone, or raising the pulse and pumping out the adrenalin to excite them. Aro, like Edward, is able the minds, but with a twist: Aro has to be in physical contact with a person in order to hear their thoughts. But, he has one advantage that Edward does not. Aro can not only hear what thoughts are crossing a person’s mind at that moment (like Edward can), he can hear every thought that has ever crossed their mind. But, like in Edward’s case, Bella is immune to Aro’s ability. And lastly, Jane has the ability to inflict the illusion of pain inside her victim’s head. Once again, Bella is an exception to this power.
So far in the Twilight series, it is apparent that Bella is an exception to any special ability that a vampire has, if it involves her mind. Bella has a very private mind—she cannot be touched there. This is why Edward, Aro, and Jane’s special abilities do not affect Bella. Their powers work inside the mind. Edward and Aro look inside the mind to read someone’s thoughts. Jane also works inside the head—she doesn’t actually inflict pain on anyone’s body; she puts the illusion of pain inside her victim’s head. This is an effective form of torture. On the converse side, what Jasper does is no illusion—he affects the physical body, slowing the pulse, and upping the endorphin level to calm someone, or raising the pulse and pumping out the adrenalin to excite them. Also, Alice works outside the mind. She doesn’t see the thought process behind the decisions, just the outcomes. So, if a vampire has a special ability that involves working inside the mind, Bella will be immune to the power.