First of all, I'm a game programmer.
I have never applied to a QA position, nor have I processed applications for QA positions.
I however do know what QA does, I work with them and I have certain expectations from them.
I've also setup QA systems and instructed people on how to use them.

Writing as I read through it:
I'll be very critical, don't take offense to this.
You did a great thing in letting others read it first.

Thank you for reading my application as a QA tester within your Company. For Years I have dreamed
about becoming part of the gaming industry as a 3D Artist, but never pursued that dream because I'm
not yet good enough. Recently, after talking with developers from Sony Online Entertainment, I realized
that the best way to get a job in the industry is by starting low, and working my way up the ladder over
the years.[/quote]
This part tells me you intend to take the job only as a bridge to a different job. It tells me when given the slightest chance you're off again.
It also tells me you're insecure about your ability.
Personally I'd scrap this section entirely. It comes off somewhat desperate.

Also, I've talked to a few people that ended up getting hired as a content designer after their excellent QA work.
However, a position in QA won't really give you an opportunity to express your ability as an artist.
Growing into the position of artist from a position in QA may actually be really hard.

Maybe someone else knows a success story here? I don't at least.

While I have not worked as a QA tester before, I'm a avid gamer since my childhood, and spend most of
my free time playing games, especially MMOs. I have, however, participated in several MMO beta
phases, and always considered those phases as a chance to make the game better for myself and
everyone else. Whenever I found a bug or other odd behavior in a game I played, I tried to collect as
much information as possible about the issue, to help the developers removing the bug.[/quote]

This isn't too bad, but I'm not sure you should be singling out MMO's here, unless you're applying specifically for a position to QA on an MMO.
If you're not, broaden it up. Express yourself as someone with wide interests and experience with a broad range of games.
Remember, for most companies you won't be just testing a single game. You'll be testing whatever it is they are developing at that moment.
You might even be testing My Little Pony Barbie Adventure 40 hours a week, be prepared to suck it up and do your job.

You might want to expand a bit on your bug hunting qualities, possibly do some more digging into the profession so you can speak their lingo.
Experience with commonly used bug tracking systems like Jira might be something to mention here if you have it. (if you don't.. get it!)

A small note here as well, you don't really help developers remove a bug. You help them identify it and reproduce it.
They'll take care of removing it. I know this is very close to what you're saying, but do note you might be dealing with certain egos that look down on testers.
By making this distinction you can show you're familiar with the position of a tester in this whole process.

I want to cover the distance from learning stage to experienced stage in this company. Thank you for
considering me as candidate and will be waiting for your feedback.[/quote]
I see what you're getting at, but it's a bit awkwardly worded.
If you mean you to state you're ready for a long term commitment and intend to grow within the compnay, just state so.
The way you phrased it might be interpreted as if you'll leave as soon as you've gathered enough experience.

Degree: Realschulabschluss[/quote]
I have no idea what this is. Nor will any English speaking company you apply for.
Translate it. Leave the original between brackets if it's important (in case there's no perfect equivalent in English)

MMO EXPERIENCE:[/quote]
Formatting in this section makes it hard to skim.
I could be an HR drone, I don't want to focus and read the entire sentences.
Add some more formatting and it easier to skim.
You could cut it down, add more white space, bold important achievements, etc.

The amount you spent on a game doesn't actually say much.
Playing games a lot does not make you a better tester. In fact, it's entirely irrelevant.
Your beta testing experience is indeed relevant, but be sure to express your contribution in such way it doesn't come off as if you only participated in the beta to get early access to play the game.
If you recall, express the kind of bugs you found and reported. Don't go in great detail, just make an effort to show you know what you're talking about.

3D ART EXPERIENCE:[/quote]
Not relevant for the position.
Companies will not hire you in QA in hopes you turn out a great 3D artist.
They hire you to test their games.

Working in QA just means you get direct access to several people working in the industry and allows you to get your application for a different position to get pushed a bit higher up on the pile.
Leave this part out entirely. All the company needs to know is you'll be good at testing their game.

SPECIAL SKILLS:[/quote]
Somewhat awkwardly worded "I am highly skilled in the use of computers and the internet" sounds terrible.
You might want to go for a bulletpoint approach here instead, just list your experience and skills.
Instead of "I learn very quickly" just "Quick learner".
Your ability to speak and write German is excellent and quite useful. Good thing you put that in there.




Alright, so I read the whole thing.
Personally, I wouldn't hire you.

Your letter didn't inspire me with confidence you could do the job.
You seemed to have little to non testing experience.
Your letter came off as somewhat desperate and suggested a lack of confidence in your ability.

Now, not all companies have very high standards for testers. Some are willing to employ anyone that applies.
But these companies also generally tend to consider their testers disposable work forces.
Don't rush to accept the first offer you get. Try to get a bit of insight in the environment you work in and the people you will interact with.
If you're completely isolated from developers (some companies don't develop out of the same building as they test) it quite reduces your chances to make the connections you need to move up.

I suggest you dig into how game QA works and the general processes they employ.
Get familiar with different bug tracking software. Get familiar with writing bug reports.

The keyword I missed the most in your letter was "reproduce". Figure out what it means in the context of QA.

No problem.

I probably should have added this, but better late than never.

You might want to look at your current position in life and determine if this is the right course of action.
If you need the money to support yourself, working in QA can get you a salary and a few connections in the industry.
However, it will not teach you anything for your intended dream job. You'll have to teach all of that to yourself outside of work hours.

Alternatively, if you're still living at home and your parents are willing to put up with you financially for several more years, you might want to get some formal education.
Teaching yourself requires a lot of determination and endurance. Being taught the art of 3D modelling might actually be a much more solid and faster path to learning the craft.
If you're good at what you do, you don't need the connections. You just apply for the job.

This may actually be a much preferred route as to be frank working in QA is quite mind numbing. You might be exhausted after a full day of work and unable to work up the energy to get back to studying 3D modelling.
Since I gather you're from Germany, I actually posted about a school I recommend in a different thread earlier: http://www.gamedev.n...-and-which-one/
There's actually quite a few of Germans attending that course.