Hi, I´m not a Photographer Guru and so aren´t my pictures.
What in your opnion ist the best tool, to get better results for poor Photos?
[FONT=“Georgia”]That’s a hard question, it really depends.
How much money you’re willing to spend, how much time you’re willing to spend editing, and what kind of editing.
If you’re just taking casual party shots of you and your friends, I’d say go with Gimp. It’s a powerful tool; Something used by many professionals here on Sitepoint, and it’s completely free!
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It should also be said that GIMP is limited to pictures that will be watched in a screen (computer, tv, etc), not for professional printing.
It is a great tool and has many of the features that the big cousin, Photoshop has…
Yet, I have to say that Photoshop is the best tool in my eyes 
Of course, it is very, very expensive but… It does have a smaller brother, Photoshop Elements, that includes most of its features but it is more reasonabled priced.
Also, if by editing a photo you don’t mean to manipulate the photo like hell but improve it with contrast, WB, exposure settings etc. then the better tool for you will be Adobe Lightroom, its much cheaper than Photoshop & it is made for photographers intending to be the digital version of dark room unlike Photoshop which is the big daddy for anything related to images/graphics & not just photos. 
A free, online solution is the Aviary suite. Specifically the Phoenix image editor. I haven’t messed around with it very much, but it’s pretty darn good in it’s own right:
You may take a look at ACDSee’s products, and specifically their ACDSee Pro Photo Manager. It’s an all-in-one solution for photo editing, managing, and publishing. It has just enough feature set a photographer would need.
[FONT=“Georgia”]Could you elabourate?
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with the tons of applications available in the market. I think the photoshop is the best application even for the layman for editing pictures .