What's the best way to raise your poisoning skill?

buy as high as you can, poison food (I heard you can only poison stuff once, but I used the same fishsteak for as long as I tried poisoning) with lesser poison until 40-45 switch to reg poison til ??? I quit after 48 I think.

Damn Quitters LOL

Anyways to the OP:
Buy/Make 255 Daggers(or 125 whichever you can fit into your house).
Set up a UOA Macro to Poison Them all(or you can do it manually and just remember which ones you have poisoned and which you haven't.
Well use normal poison to whenever you stop getting consistant gains.
THEN buy/make(better to make them), about 200 Greater Potion KEGS.
Now the "fun" part begins.
Hit that macro. Wait until you gain and stop then hit it again.
When dealing with Poisoning most people don't know that if you poison a certain object you can not gain off that until server up or until you gain in poisoning at certain skill levels.
So thats why a lot of people use the fishsteak method. Take out one fishsteak, poison, drop it in the pile again. This makes it a "new' item when removed again.

So the reason you "start" over again is because you can gain from the first dagger again.
Now why 255? I heard from an experianced poisoner if you have 255 daggers you will ALWAYS gain off 1 of those daggers if you poison them all.
Not sure if that is true though, I only used 150 daggers myself. Ran out of GP kegs at around 94ish poisoning. Been that ever since.
I can already DP on my Nox Mage and there is no point in me GMing it right now(still need to 120 all my other skills).
So thats how you GM Poisoning(I GMed it on Greak Lakes when it was remotely useful).