Bulgarian is not at all a common language. This is why it can be so hard to find a good linguist to cater for your translation needs. And, if you come across an offer, you cannot always be sure about the quality you will get, as it is an exotic tongue with an exotic alphabet you may not even be able to decipher.
That said, how can you know you are choosing the right translator?
The easiest way is to rely on word of mouth and have a linguist recommended to you by a person you know and trust. However, how many of your acquaintances know that super-perfect Bulgarian translator?
Another way is to browse the internet, but how to tell one provider from another? Everyone claims to be the best.
Here is a hint: check the translator’s clients. If she has been chosen to work for renowned organisations, then she should be good.
Next, check her specialisations: they must correspond to your translation needs, otherwise there is no guarantee for the quality you will get.