Ok now you have your dueler and are ready to fight, how do you get a slight advantage or at least not give an advantage to your opposition, through lack of knowledge, read on to find out...
Now before you rush into a duel I have found that you have periods when you are on form and periods where you are off form. Generally when you were just about to go up a combat level, i.e one more attack defence or hit till you go up a combat level is the best time to duel as you seem to be on form. You can check how soon you will go up a combat level on the combat level calculator on the Rune Tip It web site, there is a link to the calculator on the line above and to the whole website at the top left of the page. If, after using the calculator you feel you will be in a period where you are on form it is time to see if you indeed are....
Most dueling goes on in Lumbridge on world 8, so go there. I was a defence "noob" in my itenary i always carried a set of full rune (rune chain), full black, rune two hander, rune kite, rune battle axe, a super set, a diamond ammy, gloves and a bit of cash (dont worry you wont lost anything you dont stake even stackable items).
First scout a worth opponent, watch fights and see who you think you can beat. Signs to look out for are people hitting very high for their level is an indication of low defence (i.e a pker). If you are level 50 or above look out for players with rune plate, at least 32 magic is needed to get the plate so they are several levels impure. Make sure you have magic and prayer off though when dueling impures. Dont fight "madges" recognziable by their full rune at a low level and staffs. Also remember that some players try to camoflage themselfsby wearing full black then whipping out full rune as you yourslef may indeed do. If someone is pestering you for a full rune stake or similar they are probally on form and bery confident approach with caution especially if you are not on form yourself.
When you have found your ideal opponent ask them "jimmy02 stake r2h" or whatever. If they say yes take the potions super attack, defence and strength potions quickly. Check they have all been taken if not do so (tip, place an item behind them, whrn taken they will move to the other side of the item). When this has been done set the stake and start the duel. Quickly change into your full rune from your camoflage armor. Have your full rune in the first four spaces in your itenary for ease of access.
Play to your advantages if you do have prayer make sure you allow prayer to be used in the battle, conversly if you have no prayer dont fight if someone insists on haveing it on, even if you have taken potions for the fight. Think of it like this a dose of each potion from a super set is a third of 20k which is 6.5k better to lose that than a rune two hander.
A further tip i can give is get some normal potions and use these to duel for ammys. Nobody else seems to do this and it gives you a good start.
A final tactic some people like to employ is that of swapping between a kite shield and rune two hander. When ever its their turn to attack they pull out the two hander and when its their time to defend they employ the kite shield.
Obviously never duel with anything less than full health, and full equipment. If you are unsure never duel and never never restake, trust me its bad luck. If you are haveing a streak of bad luck go and train up a few level, then give it another go.
Finally enjoy dueling, good luck and remember enjoy your wins but dont be disheartened by your losses, its only a game.
Hope this guide was of help.
If there is anything i have left out or a question you want answered send me an email by using the suggestions/questions link at the top of the page on the left or the hyperlink on the above line.