Based on her magic and combat abilities.
   
I know her combat isn't that great. She was trained by the Justice League, and knows enough to get by. But what about her magic? What would you say she's like on a regular basis, at her worst and at her best?  Zatanna was said to be the most powrful member of the Justice League. Do you think she's reached her potential?

I don't know if I'd say she was the most powerful person to ever join the Justice League, however, she's certainly high on the list. She is one of the DCU's most powerful magicians. Unfortunately, like the Martian Manhunter, writers sometimes have to hand her the idiot ball to keep her from solving things with a single spell. She's certainly capable of taking on big magical threats solo.

" I don't know to much about Zatanna, but doesn't she have like almost every power . From what I have seen, she can do anything jus by speaking it. Wha are her lmitations? "

Her magic is on a pretty high level but she loses against a lot of opponents in the battle forums because of her speed. She will most likely get blitzed by many characters before she can think of a spell or open her mouth.

not that powerful, I bet Abra Kadabra is more powerful than her.

" Her magic is on a pretty high level but she loses against a lot of opponents in the battle forums because of her speed. She will most likely get blitzed by many characters before she can think of a spell or open her mouth. "

She also manipulated time and space, helping them return to the present day.    

She's DC's third or fourth most powerful sorceress who only resides on the earthly plane.
 
Unfortunately she suffers from: "The writing of Comic Book sorcerer's paradox," all... the... time
 
 http://www.comicvine.com/forums/gen-discussion/1/the-writing-of-comic-book-sorcerers-paradox/571756/

She's a top tier character, with her biggest weakness being speed. (The writers definitely need to giver her auto shields like classic DS had.)

I don't think she needs to speak to cast spells. I don't mean energy (fire, water, and the like) either. I swear I read somewhere if she can't speak she can write them backwards in her blood. That's either true and I can't remember where I read it or I made it up. Someone should check on that. 

" @mr.obvious:  In the DC Animated Universe, Zatanna has already beaten Abra Kadabra in single combat, pretty convincingly. I don't think it would be any different in the comics.   Zatanna can be the most powerful member of the Justice League or the weakest, and it all depends on the writer. She has the same problem as Doctor Strange: the capabilities of magic are seldom well-defined in comics, and what it can do is often decided upon entirely by the needs of the current plot. Therefore a magic-user's power level is open to far more interpretation than conventional superheroes whose abilities are much more cut and dried (super strength: can lift X-number of tons, super speed: can run/fly at X-mph, etc.). If the plot requires it, Dr. Strange has been used as a deux ex machina device, where he literally comes up with any magic for any situation in order to save the day. Or, someone can break his hands and render him powerless since he needs to gesture to cast spells. Same goes for Zatanna. She can come up with spells that can do literally anything the plot requires (except raise the dead). Or a relatively weak adversary can gag her and render her powerless, because if she got off a spell the whole storyline would be resolved too quickly.   As a character, Zatanna sometimes suffers from confidence issues, which keeps her from being as powerful as she could be and I think causes people to disrespect her power level. So no, I don't think she's reached her full potential yet. But I still consider her DC's "Sorceress Supreme" and she deserves a lot more respect than she usually gets.                  "

@pokeysteve Yeah, she can write spells in her blood

She is pretty powerful right now based on feats and some hints to her full power.

Currently, Enchantress proved to be superior to her magic wise. I haven't kept up with JLD. Has Zatanna surpassed her or has any character proven to her that they are more skilled at magic than her?

xoxo, -Saint Sophie

@saint_sophie: she has become way more powerful. She fended of a crazed JUstice League, and her body was possessed and she pretty much beat the entire JLD team