What kind of answers are you expecting ?
Yes , you can screw up your Anonymity by not being careful.
You should take some Time to read the Topics Patrick posted.
You get what you pay for ... (oh wait , right)
Please, go for it then, solve those Problems . Or do you know a way how we could fix them? .
There will be no 100% safety or Anonymity (it always depends on your Adversary), if you are conscious of that , then you can act accordingly.
Maybe helpful :
(DEF CON 22 - Adrian Crenshaw- Dropping Docs on Darknets: How People Got Caught)