Whichever artist you choose to commission for a Fursona image, icon, or avatar, be sure to provide that artist with a written description of that fursona - species, gender, distinctive coloring or clothing (if the character wears clothes).
Does the fursona walk upright/erect on two legs, and if so - does the character walk on toes ("Digitigrade Stance") or on the flat of his/her feet ("Plantigrade Stance")?
Is there a preferred prop associated with the fursona - a sword, a gun, a spear, a book, a staff, anything of that nature?
What is the fursona's most common or preferred emotional attitude or expression? Is there a preferred pose?
The trick is to be able to present the artist with enough information to go on, to make the appearance of your fursona unique, and pleasing to you - while at the same time, allowing the artist the creative license and flexibility that helps the artist add personality and life to your image...and yet makes it fun for the artist, as well.
Limit this description to only the visible features; the artist does not need to know the history or motivations of the fursona, as they can't be drawn.
Type up this description on a single page of paper - and if you have the language skills, perhaps in english on on side, and german on the other - and print multiple copies, to leave with individual artists who accept your commission. Include your name and contact information on this description sheet!