I figured I would post this since I've had people ask me for my build and I was too lazy to explain it at the time so I told them to find a guide somewhere (but after some searching I discovered there isn't one). So let's jump into this.
This is for a level 30 hellrushed Amazon with all skill and stat quests done (I don't bother with Anya due it's resis being bugged).
We'll be using the 86% fhr bp (gives us 5 frame recovery) at all times, 30 IAS BP for javs (9 frame throws), and 65% IAS BP for our bow (9 frame attacks).
Poison Javelin - 20
Lightning Bolt - 1
Plague Javelin - 13
Dodge - 1
Avoid - 1
Evade - 1
Magic Arrow - 1
Multiple Shot - 1
Cold Arrow - 1
Guided Arrow - 1
Str - Enough for gear
Dex - Enough for max block with your Rhyme
Vita - All other stat points go here
Energy - none
I'll list ideal gear then substitute gear (subs in italics)
1 zon, 30 frw, xx life, and 2 sockets are what you want (any other mods are icing on the cake) socket it with str/dex/@res jewels
Peasant Crown - socket it with a str/dex/@res jewel
Peace runeword (either MP or BP)
Some people consider the slow missiles proc on Peace to be BM so if you can find the space (I don't have any available slots so I tell those people to wipe up their tears) in your stash have a Vipermagi or Spirit Shroud to swap.
String of Ears - Be sure it its 15% damage reduction and 15 magic damage reduction, the other stats on it don't matter.
24 fhr, xx life, life rep, res belt - I use this for lit stack vs FoHers
2 jav&spear along with 10 ias (these are the minimum mods they should have, try to find ones with life rep and resis)
30 frw, 10 fhr, tri res boots - I use these for cold stack vs sorcs
2x Stone of Jordan
1 zon, xx life, xx mana, life rep, @ res - Try your best to find one with these mods, at minimum find one with 1 zon xx life.
Eye of Etlich
Telling of Beads
Rhyme runeword in a Bone Shield
Maiden Javs with 4 jav&spear and either 20 or 30 IAS (you'll be using the 30 IAS bp so the 10 IAS on your gloves will let you hit it with 20 IAS on jav), either rep quantity or increased stack size is a highly desirable mod (if you can't find a set with it you'll just have to be more conservative with how you throw) any other mods after that are a boon.
3 skill 15%ed 5os Ashwood Bow (socket it with 3 Shaels, a Nef, and the highest dmg jewel you can find)
Upped Rogues Bow - I'm not a fan of this option since it limits your socketing options (you can't socket it with anything with a level requirement over 25), it's damage is very low (it sort of makes up for this with it's high DS), and it requires 2 more str than an Ashwood.
Godly Duped Bow - If you have no scruples you can use one these
You end up doing a lot of charm swaps on this char
There's no cut and dry setup for how you have your inventory since a lot of it is personal preference (I probably use more frw than most people so my invent setup would look strange to them).
You want a mix of;
life/mana scs (15/12s are perfect)
frw/@res scs (3/5s are perf on ladder on nl you can find 5/5s)
3 max dmg, xx ar, frw
3 max dmg, xx ar, fhr
life res scs (either 15/5s or 15/9s, 5s are @res 9s are single resis)
With the skill layout listed and the ideal gear your plague jav dmg will be 11458-11635 over 12.6 seconds, have 42% dodge, 50% avoid, 42% evade and 51% chance of crit strike. You life, mana and bow dmg will change depending on what gear and charms you're using. Ideally you want to shoot for 1k+ life, 300+ mana, and 110+ frw with all your swaps. The 3 max dmg with mods scs are there to help your bow dmg while also covering other areas (frw and fhr) so try not to skimp on those.
Now you've got your character built and geared, your stash is set up nicely and you want to kill some people.
The first thing you should know about a plaguezon is that they're a defensive build (there are few situations where being offensive will benefit you) but they kill fast. You'll spend most of your time running away from and in circles around your opponent. Also your bow damage will never be anything to write home about but it's mainly there to keep people off balance and sometimes to deliver the coup de grace. You match up well vs most builds and by being a bit of an oddball character you can surprise people since they're not used to dueling a plaguezon.
Now on to the strategy section
Kickers - Die. This is one of your worst matchups, not entirely a lost cause but it's an uphill battle from the get go.
If they're pure kicker (no MB and traps to stunlock) you stand a much better chance vs them, they'll either throw on BoS and try to run you down or they'll DF on top of you. Lure them into a plague cloud (be ready to WSG like you never have before if they catch up to you) wait for it to do its thing then finish them off with another cloud or a GA to the face.
If it's a kicker with MB and traps your only chance is to hope they make a bad mistake, they should end you quickly but don't feel bad every build has its counter and kickers aren't seen much nowadays.
Trappers - Either die in an ugly manner, duel to a stalemate or kill them and make them very angry.
Those 3 ways are how every duel I've had with a trapper has turned out. They dictate the fight and it's up to you to try to turn it in your favour. Be very careful around these guys since they can MB and lay traps on you from farther out than you realize.
A lot of trappers will be lame and just sit in a field of traps and wait for you to come to them. When faced with this situation you have 2 options; plink away at them with your GAs from offscreen (be careful, traps shoot pretty far) until either they get bored and move out of the trapfield or you get bored of dueling someone who doesn't want to do much of anything, or you can try to rush them and dodge their traps blasts and MB and land a plague cloud on them.
An aggressive trapper (using either DF or a tele staff) is a whole different ballgame and normally doesn't end well for you. Try to get them to land in a plague cloud and do your best to avoid getting locked up.
Bowzon - Die. Seriously, you have virtually no chance against a good bowa.
CSer- They have to close the gap to you to be able to do damage, aim your jav well and have them looking greener than the Hulk before this happens.
Plaguezon - Whoever lands the first plague usually wins, dart in and out and try to hit with a cloud.
Whirlwind - As long as you fight sensibly you can make short work of these guys. Avoid their whirls, hope they try to leap at you and have a plague cloud waiting for them. Just be sure to have good frw and watch for desync from NL whirlwinds.
Conc - Free kill! One of your easiest duels, Concers are meant to be easymode melee so as long as you don't stand toe to toe with them they're no threat to you.
Singer - The biggest barb threat to you. Their damage might be even more laughable than your bow damage but they can easily get you in dodgelock if you let them get in range.
Fissure - One of the most fun duels you will have. Stay on the move but keep an eye out so you don't run into a fissure or get trapped in by well placed fissures. Use your bow to poke at them every now and then, I tend to circle around them in concentric circles (don't be obvious about it or you'll eat a fissure) until I spot an opening to rush in a plague them.
Windies - A boring but easy duel. If they're lame they'll sit back in a pack of summons with Hurricane, if they do this you can launch some GAs/Multis at them to kill their army then come in for the kill. If they try to telestomp you it becomes even easier, just have a plague cloud waiting for them and get out of the Hurricane, their health will drop in no time then you can finish them off easily.
Maulers - Free kill, easily the worst LLD char.
Fury - Watch for them to desync from high frw. They cannot damage you from range so you just have to kite them around until you can lure them into a plague cloud. Do not ever try to tank one of these unless you want a free ride back to town.
Bone necro - These make for very interesting duels. Watch out for Bone Spirits while you dodge spears, do your best not to get walled in (you're dead if you do thanks to dodgelock) and close the distance to them until you can plague them.
Blizzard - One of your hardest duels, these can easily dodgelock (using Telekinesis to get you into FHR animation, then teleing on you and spamming Frost Nova or Ice Blast) you and they kill extremely fast. Do your best to avoid being telestomped and get them to land in a plague cloud.
Lightning - These can kill you ridiculously easily, they're also almost non-existant in LLDing. Same as a blizz sorc just TStorm makes them lock you up and kill you faster.
Fireball - Widely regarded as the top lvl 30 dueler and for good reason. Extremely high damage output coupled with high mobility makes them a huge threat. A good one will will try the same thing as Blizz or Lit sorcs so try to keep standing in your poison clouds when they tele on/near you.
Firewall - Arguably the strongest sorc variant at lvl 30 also can be considered one of the top duelers period in LLD and MLD (I haven't gotten to test a high level one yet so I can't comment on that). Against a good one this will be one of your hardest duels, their mobility combined with the ridiculously high dmg of firewall will make things very tough for you. On the flipside you're also a very tough matchup for them and as long as you can keep pressure on them while avoiding FWs you can emerge victorious.
Smiter, Charger (and its variants), Liberator, V/T, T/V, Hammer, Zeal - They will try to desync using charge leaving you with three options; you can use WSGing to desync yourself until you both get bored, you can tell them to stop using flaws in the game and have a real duel, or you put your back to a wall (this can end badly vs smiters though) and keep a poison cloud around you to catch them when they get close.