How do I deal with Aversion? I practice the Dhamma &amp; I try hard to show loving-kindness, but I end up sometimes getting very mad at people or irritated. 

I try Metta meditation, but is there anything else I can do to try and calm the poison of anger? I don't want to be snappy or hateful at times, people just cause me to arise my anger at times.

Metta &amp; Appreciation!
well there is the 4 four divine abodes like you said, and beyond that, there is becoming an arhant. 

For metta and the opposite, ie anger, ill will you can find out why you get angry towards somebody. Generally, people get angry at somebody or something because they care about a thing, then somebody does something and the angry person imagine that this action of this somebody will  threaten the thing he cares about.
Then the method is that you must determine if what you care about is indeed worth caring about. It runs out that puthujjanas care about bad things and do not care about good things. So that's probably a good start for improvement. So first see if you think that caring about the thing is good or bad, then see if the buddha says it is indeed good or bad.
If the buddha disagree with you, then you better follow him, rather than whatever false ideas  popping up in your mind.

so if you want something else than metta, you have to look at wisdom, ie panna, and with the buddha, the way to get wisdom is always the same, ie this
http://obo.genaud.net/a/dhamma-vinaya/pts/an/04_fours/an04.126.wood.pts.htm#p1


  Herein, monks, a certain person lives irradiating one quarter (of the
  world) with a heart possessed of amity; so also as to the second,
  third and fourth quarter of the world; and in like manner above,
  below, across, everywhere, for all sorts and conditions, he lives
  irradiating the whole world with a heart possessed of amity that is
  widespread, grown great and boundless, free from enmity and
  untroubled.
  
  There, whatsoever conditions arise by way of form, feeling,
  perception, the activities, consciousness, those conditions he comes
  to regard as impermanent, as Ill, as a disease, as an imposthume, as a
  barb, as pain, ill-health, alien, transitory, as empty and not of the
  self.
  
  When body breaks up after death he is reobrn in the company of the
  devas of the Pure Abodes.
  
  Monks, this rebirth is not partaken of by ordinary men.


Of course getting metta is hard for anybody clinging to sensuality, ie most people. So the beginning of that and more generally of ''mediation'', ie samadhi, is always to see thoughts as you see ''objects'' of the 5 usual senses, ie just things which come and go and do not get infatuated with ideas, thoughts, dreams, fantasies and all that.
Do not base your actions on thoughts. Base your actions, ie what you do and do not do, only on what the buddha says is wisdom. (since puthujjanas do not have any wisdom, they have to memorize what wisdom is, from the buddha , then cultivate it) 

it turns out that the buddha says that there are good thoughts and there are bad thoughts.
First you must memorize what are good thoughts and what are bad thoughts, which is explained here https://www.accesstoinsight.org/tipitaka/mn/mn.019.than.html

Second you must be judging all the time, all the thoughts which pop up in the mind. This is really hard for most people, only because people think that when they have an idea, they have to act on it, that their ideas, opinions, thoughts are always good, (and ideas of other people are mostly bad).

Third, you must judge a good thoughts as good thought and bad thought as bad thought . Some people do not even do that. for instance they say that thoughts of anger sometimes are good. THe buddha says thought so anger are always bad.

fourth, you must get rid of bad thoughts and keep only good thoughts. This is hard too as long as you see thoughts, opinions, ideas, dreams as important, as above.

Fifth, the way to get the citta in samadhi is actually to keep the good thoughts and then, with the faith in the buddha, you must manage to get piti, sukha, joy (ie that the things that the buddha calls good are indeed good, which is the way to tranquilize all the stuff that the buddha says is bad.

for instance, to calm the ''bodily formation'' you have to ''enter'' the 4th jhana


  "And how is a monk calmed in his bodily fabrication? [4] There is the
  case where a monk, with the abandoning of pleasure &amp; pain — as with
  the earlier disappearance of elation &amp; distress — enters &amp; remains in
  the fourth jhana: purity of equanimity &amp; mindfulness, neither pleasure
  nor pain. This is how a monk is calmed in his bodily fabrication.


https://www.accesstoinsight.org/tipitaka/an/an10/an10.020.than.html#fnt-1
Because the buddha says that  culturing  good thoughts and joy is actually the way to get the citta into samadhi.


  "For a person endowed with virtue, consummate in virtue, there is no
  need for an act of will, 'May freedom from remorse arise in me.' It is
  in the nature of things that freedom from remorse arises in a person
  endowed with virtue, consummate in virtue.
  
  "For a person free from remorse, there is no need for an act of will,
  'May joy arise in me.' It is in the nature of things that joy arises
  in a person free from remorse.
  
  "For a joyful person, there is no need for an act of will, 'May
  rapture arise in me.' It is in the nature of things that rapture
  arises in a joyful person.
  
  "For a rapturous person, there is no need for an act of will, 'May my
  body be serene.' It is in the nature of things that a rapturous person
  grows serene in body.
  
  "For a person serene in body, there is no need for an act of will,
  'May I experience pleasure.' It is in the nature of things that a
  person serene in body experiences pleasure.
  
  "For a person experiencing pleasure, there is no need for an act of
  will, 'May my mind grow concentrated.' It is in the nature of things
  that the mind of a person experiencing pleasure grows concentrated.
  
  "For a person whose mind is concentrated, there is no need for an act
  of will, 'May I know &amp; see things as they actually are.' It is in the
  nature of things that a person whose mind is concentrated knows &amp; sees
  things as they actually are.
  
  "For a person who knows &amp; sees things as they actually are, there is
  no need for an act of will, 'May I feel disenchantment.' It is in the
  nature of things that a person who knows &amp; sees things as they
  actually are feels disenchantment.


https://www.accesstoinsight.org/tipitaka/an/an11/an11.002.than.html

now back to metta

first the buddha says that to avoid aversion, you have to cultivate ''Good will as an awareness-release''


  "[Then if they ask,] 'But what, friends, is the reason, what the
  cause, why unarisen aversion does not arise, or arisen aversion is
  abandoned?'
  
  'Good will as an awareness-release,' it should be said.
  
  'For one who attends appropriately to good will as an
  awareness-release, unarisen aversion does not arise and arisen
  aversion is abandoned...'


http://obo.genaud.net/dhamma-vinaya/ati/an/03_threes/an03.068.than.ati.htm#p1

but then there ''two kinds of view'' about metta. the view of the puthujjanas and of course the way better view of the non-puthujjanas because it is wisdom and not really a view,
http://obo.genaud.net/dhamma-vinaya/ati/an/04_fours/an04.125.than.ati.htm


  "There is the case where an individual keeps pervading the first
  direction[1] — as well as the second direction, the third, and the
  fourth — with an awareness imbued with good will.
  
  Thus he keeps pervading above, below, and all around, everywhere and
  in every respect the all-encompassing cosmos with an awareness imbued
  with good will: abundant, expansive, immeasurable, free from
  hostility, free from ill will.
  
  He savors that, longs for that, finds satisfaction through that.
  
  Staying there — fixed on that, dwelling there often, not falling away
  from that — then when he dies he reappears in conjunction with the
  devas of Brahma's retinue.
  
  The devas of Brahma's retinue, monks, have a life-span of an eon.
  
  A run-of-the-mill person having stayed there, having used up all the
  life-span of those devas, goes to hell, to the animal womb, to the
  state of the hungry shades.
  
  But a disciple of the Blessed One, having stayed there, having used up
  all the life-span of those devas, is unbound right in that state of
  being.
  
  This, monks, is the difference, this the distinction, this the
  distinguishing factor, between an educated disciple of the noble ones
  and an uneducated run-of-the-mill person, when there is a destination,
  a reappearing.


Do not confuse the view of the puthujjanas with the wisdom about metta.

now concretely the good will is explained here
http://obo.genaud.net/dhamma-vinaya/ati/kd/snp/snp.1-08.than.ati.htm


  Do not do the slightest thing that the wise would later censure.
  
  Think: Happy, at rest, may all beings be happy at heart. Whatever
  beings there may be,
      weak or strong, without exception,
      long, large,
      middling, short,
      subtle, blatant,
      seen and unseen,
      near and far,
      born and seeking birth: May all beings be happy at heart.
  
  Let no one deceive another or despise anyone anywhere, or through
  anger or irritation wish for another to suffer.
  
  As a mother would risk her life to protect her child, her only child,
  even so should one cultivate a limitless heart with regard to all
  beings. With good will for the entire cosmos, cultivate a limitless
  heart: Above, below, and all around, unobstructed, without enmity or
  hate. Whether standing, walking, sitting, or lying down,
      as long as one is alert, one should be resolved on this mindfulness. This is called a sublime abiding here and now.
  
  Not taken with views, but virtuous and consummate in vision, having
  subdued desire for sensual pleasures,
      one never again
      will lie in the womb.