This is to kill the lvl 110 dragon for the Dragon Slayer Quest
Well first off you need your stats. It's good to have a semi balanced set of stats. Some people have said to have done it on 40, 40, 41, 40, so having your stats at 45, 45, 45, 45 or somewhere along those lines should be good.
I'm suggesting to get yourself to a combat lvl of around 50 and over to be on the safe side. If your level 55+ then you'll be having some fun unless the enemy lag hits

Equipment
Every warrior has their stats, but armour also plays a huge part in combat. So this is a suggestive list of what you could bring to fight this monster.

Armour:
Rune Large, Rune Chain/Addy plate (Rune chain is only 1 point more than addy plate) and Rune/Addy legs.
Or you can just go for full Addy if you dont want to run the risk of dying and losing some valuble armour(like myself)
You MUST have your Anti Dragon Breath Shield equipped in this battle otherwise the dragons breath could hit you for 50's(Some say 60's) which could be a 1hit 0wnage on the dragons part.

Weapons:
Rune Battle Axe or Rune long. Rune long has a higher aim but a lower power than a Battle Axe. The choice is up to you
Rune long: Aim 50, Power 50
Rune Battle: Aim 47, Power 64

Amulets:
Depending if you want to hit higher, Get hit for less or both, then an amulet may help.
Ruby Ammy: +10 Weapon power
Emerald Ammy: +7 Armour
Diamond Ammy: +7 Weapon aim, power, armour, magic

Food:
If your training your stats or trying to get a rare drop, you need food to stay training longer and to heal yourself when your Hit Points get low. Food is an absolute must while fighting this dragon. 17-20 Lobsters/Swordfish should cover you for the fight. Don't bring meat like I did when I first tried. Run when your about half your hits and eat 2-3 Lobs/Swords and fight it again, run and heal, fight etc...
Lobsters heal 12hp each while Swordfish heal 14.
Don't eat more than you have to, you'll be wasting food

Other Items:
1 Strength Potion will be enough to last the fight, dont bring more than 2.

Teleportation runes!
If you look like or you think your going to die because you're out of food, these are a must if you don't want to die. You can come back with more food later with no lost armour

I think that's all thats involved in Dragon slaying If I've left anything out or any other tips I may have missed, feel free to PM me.

Happy Dragon Slaying